High Netty CVEs

50 CVEs, 1 exploited, 2 protected by Waratek

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Overview 50 matches · 2 protected · 1 exploited · 1 CISA KEV · 1 public PoC · 1 EPSS ≥ 0.5

50matches 2protected4.0% 1exploited2.0% 1CISA KEV2.0% 1public PoC2.0% 1EPSS ≥ 0.52.0%

Protected by Waratek 2 4.0% Rule in development 0 0.0% Mitigation candidate 1 2.0% No exploit published 47 94.0%

Critical 0 0.0% High 50 100.0% Medium 0 0.0% Low 0 0.0% None 0 0.0% Unknown 0 0.0%

blocked by ARMR today 2 4.0% partly blocked 0 0.0% not blocked 48 96.0% not established 0 0.0% unrecorded 0 0.0%

Exploited 1 2.0% Working exploit published 0 0.0% Proof of concept only 12 24.0% Forecast only 0 0.0% No public exploit 37 74.0%

split by StatusSeverityProtectionExploit maturity peak 40 / year

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CVE	Severity	Published▾	Status	Exploitation	Description
CVE-2026-54251	High	2026-09-15	No exploit published	No public exploit	netty-incubator-codec-ohttp implements Oblivious HTTP (OHTTP) gateway and client functionality using Netty. Prior to 0.0.23.Final, the OHTTP gateway decryption path in codec-ohttp/src/main/java/io/netty/incubator/codec/ohttp/OHttpRequestResponseContext.java allocates a pooled direct ByteBuf for decrypted plaintext before the AEAD tag is verified. When an invalid tag causes decryptChunk() to throw CryptoException, OHttpRequestResponseContext.decodeChunk() does not release the ByteBuf because the allocation is not guarded by try/finally. Repeated invalid encrypted requests can therefore leak native off-heap memory until the gateway is unable to continue serving requests. This issue is fixed in version 0.0.23.Final.
CVE-2026-75596	High	2026-08-19	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, the default io.netty.handler.ssl.SniHandler constructors use the pre-handshake ClientHello aggregation path in handler/src/main/java/io/netty/handler/ssl/SslClientHelloHandler.java at io.netty.handler.ssl.SslClientHelloHandler#decode, where handshakeBuffer.clear() and writeBytes() recopy all previously received body bytes for every additional TLS record. An unauthenticated remote peer can advertise a large ClientHello and deliver its body in thousands of tiny records, causing quadratic CPU work on the event loop before the TLS handshake completes and degrading TLS handling for other clients. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
CVE-2026-59903	High	2026-08-17	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse authenticated responses across users and disclose sensitive information. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
CVE-2026-59902	High	2026-08-17	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.sctp.SctpMessageCompletionHandler limits incomplete messages and fragment counts but not maxBufferedBytes, allowing unauthenticated peers to exhaust memory with large SCTP fragments. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
CVE-2026-73508	High	2026-08-13	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.dns.AbstractDnsRecord, io.netty.handler.codec.dns.DefaultDnsRecordDecoder.decodeRecord(), and io.netty.handler.codec.dns.DnsCodecUtil.decompressDomainName() failed to release retained or newly allocated ByteBuf objects when IDN.toASCII() or encodeDomainName() rejected a malformed domain name, allowing unauthenticated remote DNS packets to leak direct memory incrementally until denial of service. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-73507	High	2026-08-13	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.xml.XmlFrameDecoder.decode() failed to preserve closing-tag parser state across invocations, so an unauthenticated remote attacker could trickle-feed repeated </ sequences that repeatedly rescanned the accumulated buffer and exhausted an EventLoop thread's CPU, causing denial of service with a maxFrameLength of 1 MB. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-59901	High	2026-07-29	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the `Bzip2Decoder` handler in Netty's compression codec pipeline is vulnerable to a denial-of-service attack through a malformed bzip2 stream that permanently captures the event-loop thread in an infinite loop. The vulnerability exists in the run-length encoding (RLE) state machine within [`Bzip2BlockDecompressor.read()`]. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-56822	High	2026-07-29	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator forwards the SslHandshakeCompletionEvent before the asynchronous OCSP validation completes. This allows the client's downstream handlers to send sensitive application data (e.g., HTTP requests) to a revoked server before the channel is closed by the OCSP check. n io.netty.handler.ssl.ocsp.OcspServerCertificateValidator#userEventTriggered, when an SslHandshakeCompletionEvent is received, the validator immediately calls ctx.fireUserEventTriggered(evt). It then initiates an asynchronous OCSP query using OcspClient.query. Because the handshake completion event is forwarded immediately, downstream handlers in the client's pipeline are notified that the TLS handshake is successful. They may then begin reading and processing incoming application data or sending outgoing data. If the OCSP response later indicates the server's certificate is REVOKED, the validator closes the channel, but by this time, the client may have already leaked sensitive data to a revoked server or processed malicious responses from it. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-56821	High	2026-07-29	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response to bypass revocation of a since-revoked certificate. Exploitation can lead to certificate revocation bypass via replay of an expired OCSP response. Any application using OcspServerCertificateValidator is affected; a revoked certificate can be accepted. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-56819	High	2026-07-21	No exploit published	Proof of concept only	Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct `ByteBuf` per HTTP/2 `DATA` frame in applications that enable HTTP/2 content decompression via `DelegatingDecompressorFrameListener`. When a `DATA` frame is processed for a stream whose decompressor has already been closed, `Http2Decompressor.decompress(...)` calls `decompressor.writeInbound(data.retain())` and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-56817	High	2026-07-21	Protected by Waratek	No public exploit	Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, any caller that can deliver bytes to a Netty channel pipeline containing `XmlDecoder` can send XML with a `DOCTYPE` declaration to an `AsyncXMLInputFactory` instantiated with no security configuration, leaving DTD and entity handling active depending on Aalto XML async parser behavior and creating conditional XML external entity risk. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-56816	High	2026-07-21	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.
CVE-2026-56745	High	2026-07-21	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-55851	High	2026-07-21	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final up to (but not including) 4.2.16.Final, and 4.1.0.Final up to (but not including) 4.1.135, the `HAProxyMessageDecoder` in Netty's `codec-haproxy` module performs protocol version detection by reading the 13th byte as a signed Java `byte` and widening it to `int` without masking; a PROXY protocol v2 binary prefix followed by version byte `0xFF` sign-extends to `-1`, collides with the decoder's need-more-data sentinel, and causes `ByteToMessageDecoder` to accumulate inbound bytes in an unbounded `cumulation` buffer until direct memory is exhausted. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-55833	High	2026-07-21	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-55831	High	2026-07-21	No exploit published	Proof of concept only	Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-44891	High	2026-07-17	No exploit published	Proof of concept only	Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.stomp.StompSubframeDecoder fails to limit the total number of headers or their cumulative size per frame, and the maxLineLength parameter only restricts individual header lines. An attacker can send a large number of short headers that are accumulated in memory inside DefaultStompHeadersSubframe until the JVM throws an OutOfMemoryError, causing denial of service for servers exposing a STOMP endpoint based on StompSubframeDecoder. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVE-2026-50011	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, RedisArrayAggregator pre-allocates ArrayList with initial capacity equal to the RESP array element count declared in an array header. That count is taken from the wire before the corresponding child messages exist. A small malicious header can claim a huge initial capacity. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-50010	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SimpleTrustManagerFactory.engineGetTrustManagers() and related paths wrap any user-supplied plain X509TrustManager in X509TrustManagerWrapper, which extends X509ExtendedTrustManager but implements the 3-arg checkServerTrusted(chain, authType, SSLEngine) by discarding the SSLEngine and calling the 2-arg delegate. Because the object now IS an X509ExtendedTrustManager, neither SunJSSE's internal AbstractTrustManagerWrapper nor Netty's own OpenSslX509TrustManagerWrapper will re-wrap it to add endpoint-identification. Consequently, even though Netty 4.2 sets endpointIdentificationAlgorithm="HTTPS" by default, a client built with `SslContextBuilder.forClient().trustManager(somePlainX509TrustManager)` performs no hostname verification at all. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-48748	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.
CVE-2026-48059	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-48043	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In netty-codec-http2 prior to versions 4.1.135.Final and 4.2.15.Final, the `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-48006	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the RedisArrayAggregator handler permanently leaks pooled direct-memory buffers when a Redis pipeline connection closes before a RESP array aggregate completes. The handler retains child messages in per-handler state (`depths` field) but defines no `channelInactive`, `handlerRemoved`, or `exceptionCaught` method to release them when the pipeline tears down. Because the leaked buffers are slices of `PooledByteBufAllocator` chunks, they prevent those chunks from being returned to the JVM-wide direct-memory pool. Repeated connection churn by any network peer monotonically drains this shared pool, eventually causing allocation failures on all Netty channels in the process. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-46340	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a new CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-45416	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-44894	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. NoQuicTokenHandler is the tokenHandler used when the application does not set one. Prior to version 4.2.15.Final, its writeToken() returns false (server will not send Retry — acceptable), but validateToken() unconditionally `return 0`. In QuicheQuicServerCodec.handlePacket(), a non-negative return from validateToken() is interpreted as 'token is valid, ODCID starts at offset 0', causing the server to call quiche_accept as if the client's address had been validated by a Retry round-trip. Per RFC 9000 §8.1, a validated address lifts the 3× anti-amplification send limit. Thus any attacker who includes ANY non-empty token bytes in an Initial packet — with a spoofed victim source IP — causes the Netty server to treat the victim as validated and reflect full-size handshake flights (certificates, etc.) toward it without the 3× cap. The correct 'no token handler' semantics would be to return -1 (invalid) so the normal un-validated path and amplification limit apply. Version 4.2.15.Final patches the issue.
CVE-2026-44893	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2_TYPE_SSL TLV, HAProxyMessage.readNextTLV() first calls `header.retainedSlice(header.readerIndex(), length)` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on the pooled cumulation buffer is never released. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-44892	High	2026-06-12	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. Prior to version 4.2.15.Final, the default configuration of the `Http3ConnectionHandler` in the Netty HTTP/3 codec lacks an enforced maximum header size limit. When a peer does not explicitly specify `HTTP3_SETTINGS_MAX_FIELD_SECTION_SIZE`, the implementation defaults to an unbounded limit. This insecure default configuration allows a malicious client or server to send an enormous number of headers, leading to a memory exhaustion Denial of Service via an `OutOfMemoryError`. Version 4.2.15.Final contains a patch.
CVE-2026-44890	High	2026-06-11	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending crafted Redis payloads across multiple connections without `\r\n`. This exhausts the server's direct memory pool (OutOfDirectMemoryError), preventing legitimate connections from being processed. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-44250	High	2026-06-11	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending a crafted Redis payload with deeply nested arrays. This forces the server to allocate a massive number of state objects and collections, leading to memory exhaustion and an OutOfMemoryError. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-44249	High	2026-06-11	No exploit published	No public exploit	Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
CVE-2026-44248	High	2026-05-13	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-42587	High	2026-05-13	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-42586	High	2026-05-13	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the Netty Redis codec encoder (RedisEncoder) writes user-controlled string content directly to the network output buffer without validating or sanitizing CRLF (\r\n) characters. Since the Redis Serialization Protocol (RESP) uses CRLF as the command/response delimiter, an attacker who can control the content of a Redis message can inject arbitrary Redis commands or forge fake responses. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-42585	High	2026-05-13	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-42583	High	2026-05-13	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Lz4FrameDecoder allocates a ByteBuf of size decompressedLength (up to 32 MB per block) before LZ4 runs. A peer only needs a 21-byte header plus compressedLength payload bytes - 22 bytes if compressedLength == 1 - to force that allocation. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-42582	High	2026-05-13	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final, when decoding header blocks, the non-Huffman branch of io.netty.handler.codec.http3.QpackDecoder#decodeHuffmanEncodedLiteral may execute new byte[length] for a string literal before verifying that length bytes are actually present in the compressed field section. The wire encoding allows a very large length to be expressed in few bytes. There is no check that length <= in.readableBytes() before new byte[length]. This vulnerability is fixed in 4.2.13.Final.
CVE-2026-42577	High	2026-05-13	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.
CVE-2026-33871	High	2026-03-27	No exploit published	No public exploit	Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.
CVE-2026-33870	High	2026-03-27	No exploit published	Proof of concept only	Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.
CVE-2025-24970	High	2025-02-10	No exploit published	Proof of concept only	Netty, an asynchronous, event-driven network application framework, has a vulnerability starting in version 4.1.91.Final and prior to version 4.1.118.Final. When a special crafted packet is received via SslHandler it doesn't correctly handle validation of such a packet in all cases which can lead to a native crash. Version 4.1.118.Final contains a patch. As workaround its possible to either disable the usage of the native SSLEngine or change the code manually.
CVE-2024-40642	High	2024-07-18	No exploit published	No public exploit	The netty incubator codec.bhttp is a java language binary http parser. In affected versions the `BinaryHttpParser` class does not properly validate input values thus giving attackers almost complete control over the HTTP requests constructed from the parsed output. Attackers can abuse several issues individually to perform various injection attacks including HTTP request smuggling, desync attacks, HTTP header injections, request queue poisoning, caching attacks and Server Side Request Forgery (SSRF). Attacker could also combine several issues to create well-formed messages for other text-based protocols which may result in attacks beyond the HTTP protocol. The BinaryHttpParser class implements the readRequestHead method which performs most of the relevant parsing of the received request. The data structure prefixes values with a variable length integer value. The parsing code below first gets the lengths of the values from the prefixed variable length integer. After it has all of the lengths and calculates all of the indices, the parser casts the applicable slices of the ByteBuf to String. Finally, it passes these values into a new `DefaultBinaryHttpRequest` object where no further parsing or validation occurs. Method is partially validated while other values are not validated at all. Software that relies on netty to apply input validation for binary HTTP data may be vulnerable to various injection and protocol based attacks. This issue has been addressed in version 0.0.13.Final. Users are advised to upgrade. There are no known workarounds for this vulnerability.
CVE-2023-44487	High	2023-10-10	Mitigation candidate	Exploited	The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
CVE-2023-4586	High	2023-10-04	No exploit published	No public exploit	A vulnerability was found in the Hot Rod client. This security issue occurs as the Hot Rod client does not enable hostname validation when using TLS, possibly resulting in a man-in-the-middle (MITM) attack.
CVE-2022-41881	High	2022-12-12	No exploit published	Proof of concept only	Netty project is an event-driven asynchronous network application framework. In versions prior to 4.1.86.Final, a StackOverflowError can be raised when parsing a malformed crafted message due to an infinite recursion. This issue is patched in version 4.1.86.Final. There is no workaround, except using a custom HaProxyMessageDecoder.
CVE-2021-37136	High	2021-10-19	Protected by Waratek	No public exploit	The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocation size used during decompression). All users of Bzip2Decoder are affected. The malicious input can trigger an OOME and so a DoS attack
CVE-2020-7238	High	2020-01-27	No exploit published	No public exploit	Netty 4.1.43.Final allows HTTP Request Smuggling because it mishandles Transfer-Encoding whitespace (such as a [space]Transfer-Encoding:chunked line) and a later Content-Length header. This issue exists because of an incomplete fix for CVE-2019-16869.
CVE-2019-16869	High	2019-09-26	No exploit published	No public exploit	Netty before 4.1.42.Final mishandles whitespace before the colon in HTTP headers (such as a "Transfer-Encoding : chunked" line), which leads to HTTP request smuggling.
CVE-2015-2156	High	2017-10-18	No exploit published	No public exploit	Netty before 3.9.8.Final, 3.10.x before 3.10.3.Final, 4.0.x before 4.0.28.Final, and 4.1.x before 4.1.0.Beta5 and Play Framework 2.x before 2.3.9 might allow remote attackers to bypass the httpOnly flag on cookies and obtain sensitive information by leveraging improper validation of cookie name and value characters.
CVE-2016-4970	High	2017-04-13	No exploit published	No public exploit	handler/ssl/OpenSslEngine.java in Netty 4.0.x before 4.0.37.Final and 4.1.x before 4.1.1.Final allows remote attackers to cause a denial of service (infinite loop).

CVE

Severity

Published▾

Status

Exploitation

Description

CVE-2026-54251

High

2026-09-15

No exploit published

No public exploit

netty-incubator-codec-ohttp implements Oblivious HTTP (OHTTP) gateway and client functionality using Netty. Prior to 0.0.23.Final, the OHTTP gateway decryption path in codec-ohttp/src/main/java/io/netty/incubator/codec/ohttp/OHttpRequestResponseContext.java allocates a pooled direct ByteBuf for decrypted plaintext before the AEAD tag is verified. When an invalid tag causes decryptChunk() to throw CryptoException, OHttpRequestResponseContext.decodeChunk() does not release the ByteBuf because the allocation is not guarded by try/finally. Repeated invalid encrypted requests can therefore leak native off-heap memory until the gateway is unable to continue serving requests. This issue is fixed in version 0.0.23.Final.

CVE-2026-75596

High

2026-08-19

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, the default io.netty.handler.ssl.SniHandler constructors use the pre-handshake ClientHello aggregation path in handler/src/main/java/io/netty/handler/ssl/SslClientHelloHandler.java at io.netty.handler.ssl.SslClientHelloHandler#decode, where handshakeBuffer.clear() and writeBytes() recopy all previously received body bytes for every additional TLS record. An unauthenticated remote peer can advertise a large ClientHello and deliver its body in thousands of tiny records, causing quadratic CPU work on the event loop before the TLS handshake completes and degrading TLS handling for other clients. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVE-2026-59903

High

2026-08-17

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse authenticated responses across users and disclose sensitive information. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVE-2026-59902

High

2026-08-17

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.sctp.SctpMessageCompletionHandler limits incomplete messages and fragment counts but not maxBufferedBytes, allowing unauthenticated peers to exhaust memory with large SCTP fragments. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVE-2026-73508

High

2026-08-13

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.dns.AbstractDnsRecord, io.netty.handler.codec.dns.DefaultDnsRecordDecoder.decodeRecord(), and io.netty.handler.codec.dns.DnsCodecUtil.decompressDomainName() failed to release retained or newly allocated ByteBuf objects when IDN.toASCII() or encodeDomainName() rejected a malformed domain name, allowing unauthenticated remote DNS packets to leak direct memory incrementally until denial of service. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-73507

High

2026-08-13

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.xml.XmlFrameDecoder.decode() failed to preserve closing-tag parser state across invocations, so an unauthenticated remote attacker could trickle-feed repeated </ sequences that repeatedly rescanned the accumulated buffer and exhausted an EventLoop thread's CPU, causing denial of service with a maxFrameLength of 1 MB. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-59901

High

2026-07-29

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the `Bzip2Decoder` handler in Netty's compression codec pipeline is vulnerable to a denial-of-service attack through a malformed bzip2 stream that permanently captures the event-loop thread in an infinite loop. The vulnerability exists in the run-length encoding (RLE) state machine within [`Bzip2BlockDecompressor.read()`]. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-56822

High

2026-07-29

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator forwards the SslHandshakeCompletionEvent before the asynchronous OCSP validation completes. This allows the client's downstream handlers to send sensitive application data (e.g., HTTP requests) to a revoked server before the channel is closed by the OCSP check. n io.netty.handler.ssl.ocsp.OcspServerCertificateValidator#userEventTriggered, when an SslHandshakeCompletionEvent is received, the validator immediately calls ctx.fireUserEventTriggered(evt). It then initiates an asynchronous OCSP query using OcspClient.query. Because the handshake completion event is forwarded immediately, downstream handlers in the client's pipeline are notified that the TLS handshake is successful. They may then begin reading and processing incoming application data or sending outgoing data. If the OCSP response later indicates the server's certificate is REVOKED, the validator closes the channel, but by this time, the client may have already leaked sensitive data to a revoked server or processed malicious responses from it. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-56821

High

2026-07-29

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response to bypass revocation of a since-revoked certificate. Exploitation can lead to certificate revocation bypass via replay of an expired OCSP response. Any application using OcspServerCertificateValidator is affected; a revoked certificate can be accepted. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-56819

High

2026-07-21

No exploit published

Proof of concept only

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct `ByteBuf` per HTTP/2 `DATA` frame in applications that enable HTTP/2 content decompression via `DelegatingDecompressorFrameListener`. When a `DATA` frame is processed for a stream whose decompressor has already been closed, `Http2Decompressor.decompress(...)` calls `decompressor.writeInbound(data.retain())` and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-56817

High

2026-07-21

Protected by Waratek

No public exploit

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, any caller that can deliver bytes to a Netty channel pipeline containing `XmlDecoder` can send XML with a `DOCTYPE` declaration to an `AsyncXMLInputFactory` instantiated with no security configuration, leaving DTD and entity handling active depending on Aalto XML async parser behavior and creating conditional XML external entity risk. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-56816

High

2026-07-21

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.

CVE-2026-56745

High

2026-07-21

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-55851

High

2026-07-21

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final up to (but not including) 4.2.16.Final, and 4.1.0.Final up to (but not including) 4.1.135, the `HAProxyMessageDecoder` in Netty's `codec-haproxy` module performs protocol version detection by reading the 13th byte as a signed Java `byte` and widening it to `int` without masking; a PROXY protocol v2 binary prefix followed by version byte `0xFF` sign-extends to `-1`, collides with the decoder's need-more-data sentinel, and causes `ByteToMessageDecoder` to accumulate inbound bytes in an unbounded `cumulation` buffer until direct memory is exhausted. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-55833

High

2026-07-21

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-55831

High

2026-07-21

No exploit published

Proof of concept only

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-44891

High

2026-07-17

No exploit published

Proof of concept only

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.stomp.StompSubframeDecoder fails to limit the total number of headers or their cumulative size per frame, and the maxLineLength parameter only restricts individual header lines. An attacker can send a large number of short headers that are accumulated in memory inside DefaultStompHeadersSubframe until the JVM throws an OutOfMemoryError, causing denial of service for servers exposing a STOMP endpoint based on StompSubframeDecoder. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVE-2026-50011

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, RedisArrayAggregator pre-allocates ArrayList with initial capacity equal to the RESP array element count declared in an array header. That count is taken from the wire before the corresponding child messages exist. A small malicious header can claim a huge initial capacity. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-50010

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SimpleTrustManagerFactory.engineGetTrustManagers() and related paths wrap any user-supplied plain X509TrustManager in X509TrustManagerWrapper, which extends X509ExtendedTrustManager but implements the 3-arg checkServerTrusted(chain, authType, SSLEngine) by discarding the SSLEngine and calling the 2-arg delegate. Because the object now IS an X509ExtendedTrustManager, neither SunJSSE's internal AbstractTrustManagerWrapper nor Netty's own OpenSslX509TrustManagerWrapper will re-wrap it to add endpoint-identification. Consequently, even though Netty 4.2 sets endpointIdentificationAlgorithm="HTTPS" by default, a client built with `SslContextBuilder.forClient().trustManager(somePlainX509TrustManager)` performs no hostname verification at all. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-48748

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.

CVE-2026-48059

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-48043

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In netty-codec-http2 prior to versions 4.1.135.Final and 4.2.15.Final, the `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-48006

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the RedisArrayAggregator handler permanently leaks pooled direct-memory buffers when a Redis pipeline connection closes before a RESP array aggregate completes. The handler retains child messages in per-handler state (`depths` field) but defines no `channelInactive`, `handlerRemoved`, or `exceptionCaught` method to release them when the pipeline tears down. Because the leaked buffers are slices of `PooledByteBufAllocator` chunks, they prevent those chunks from being returned to the JVM-wide direct-memory pool. Repeated connection churn by any network peer monotonically drains this shared pool, eventually causing allocation failures on all Netty channels in the process. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-46340

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-45416

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-44894

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. NoQuicTokenHandler is the tokenHandler used when the application does not set one. Prior to version 4.2.15.Final, its writeToken() returns false (server will not send Retry — acceptable), but validateToken() unconditionally `return 0`. In QuicheQuicServerCodec.handlePacket(), a non-negative return from validateToken() is interpreted as 'token is valid, ODCID starts at offset 0', causing the server to call quiche_accept as if the client's address had been validated by a Retry round-trip. Per RFC 9000 §8.1, a validated address lifts the 3× anti-amplification send limit. Thus any attacker who includes ANY non-empty token bytes in an Initial packet — with a spoofed victim source IP — causes the Netty server to treat the victim as validated and reflect full-size handshake flights (certificates, etc.) toward it without the 3× cap. The correct 'no token handler' semantics would be to return -1 (invalid) so the normal un-validated path and amplification limit apply. Version 4.2.15.Final patches the issue.

CVE-2026-44893

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2_TYPE_SSL TLV, HAProxyMessage.readNextTLV() first calls `header.retainedSlice(header.readerIndex(), length)` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on the pooled cumulation buffer is never released. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-44892

High

2026-06-12

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. Prior to version 4.2.15.Final, the default configuration of the `Http3ConnectionHandler` in the Netty HTTP/3 codec lacks an enforced maximum header size limit. When a peer does not explicitly specify `HTTP3_SETTINGS_MAX_FIELD_SECTION_SIZE`, the implementation defaults to an unbounded limit. This insecure default configuration allows a malicious client or server to send an enormous number of headers, leading to a memory exhaustion Denial of Service via an `OutOfMemoryError`. Version 4.2.15.Final contains a patch.

CVE-2026-44890

High

2026-06-11

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending crafted Redis payloads across multiple connections without `\r\n`. This exhausts the server's direct memory pool (OutOfDirectMemoryError), preventing legitimate connections from being processed. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-44250

High

2026-06-11

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending a crafted Redis payload with deeply nested arrays. This forces the server to allocate a massive number of state objects and collections, leading to memory exhaustion and an OutOfMemoryError. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-44249

High

2026-06-11

No exploit published

No public exploit

Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVE-2026-44248

High

2026-05-13

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVE-2026-42587

High

2026-05-13

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVE-2026-42586

High

2026-05-13

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the Netty Redis codec encoder (RedisEncoder) writes user-controlled string content directly to the network output buffer without validating or sanitizing CRLF (\r\n) characters. Since the Redis Serialization Protocol (RESP) uses CRLF as the command/response delimiter, an attacker who can control the content of a Redis message can inject arbitrary Redis commands or forge fake responses. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVE-2026-42585

High

2026-05-13

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVE-2026-42583

High

2026-05-13

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Lz4FrameDecoder allocates a ByteBuf of size decompressedLength (up to 32 MB per block) before LZ4 runs. A peer only needs a 21-byte header plus compressedLength payload bytes - 22 bytes if compressedLength == 1 - to force that allocation. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVE-2026-42582

High

2026-05-13

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final, when decoding header blocks, the non-Huffman branch of io.netty.handler.codec.http3.QpackDecoder#decodeHuffmanEncodedLiteral may execute new byte[length] for a string literal before verifying that length bytes are actually present in the compressed field section. The wire encoding allows a very large length to be expressed in few bytes. There is no check that length <= in.readableBytes() before new byte[length]. This vulnerability is fixed in 4.2.13.Final.

CVE-2026-42577

High

2026-05-13

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.

CVE-2026-33871

High

2026-03-27

No exploit published

No public exploit

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVE-2026-33870

High

2026-03-27

No exploit published

Proof of concept only

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVE-2025-24970

High

2025-02-10

No exploit published

Proof of concept only

Netty, an asynchronous, event-driven network application framework, has a vulnerability starting in version 4.1.91.Final and prior to version 4.1.118.Final. When a special crafted packet is received via SslHandler it doesn't correctly handle validation of such a packet in all cases which can lead to a native crash. Version 4.1.118.Final contains a patch. As workaround its possible to either disable the usage of the native SSLEngine or change the code manually.

CVE-2024-40642

High

2024-07-18

No exploit published

No public exploit

The netty incubator codec.bhttp is a java language binary http parser. In affected versions the `BinaryHttpParser` class does not properly validate input values thus giving attackers almost complete control over the HTTP requests constructed from the parsed output. Attackers can abuse several issues individually to perform various injection attacks including HTTP request smuggling, desync attacks, HTTP header injections, request queue poisoning, caching attacks and Server Side Request Forgery (SSRF). Attacker could also combine several issues to create well-formed messages for other text-based protocols which may result in attacks beyond the HTTP protocol. The BinaryHttpParser class implements the readRequestHead method which performs most of the relevant parsing of the received request. The data structure prefixes values with a variable length integer value. The parsing code below first gets the lengths of the values from the prefixed variable length integer. After it has all of the lengths and calculates all of the indices, the parser casts the applicable slices of the ByteBuf to String. Finally, it passes these values into a new `DefaultBinaryHttpRequest` object where no further parsing or validation occurs. Method is partially validated while other values are not validated at all. Software that relies on netty to apply input validation for binary HTTP data may be vulnerable to various injection and protocol based attacks. This issue has been addressed in version 0.0.13.Final. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CVE-2023-44487

High

2023-10-10

Mitigation candidate

Exploited

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

CVE-2023-4586

High

2023-10-04

No exploit published

No public exploit

A vulnerability was found in the Hot Rod client. This security issue occurs as the Hot Rod client does not enable hostname validation when using TLS, possibly resulting in a man-in-the-middle (MITM) attack.

CVE-2022-41881

High

2022-12-12

No exploit published

Proof of concept only

Netty project is an event-driven asynchronous network application framework. In versions prior to 4.1.86.Final, a StackOverflowError can be raised when parsing a malformed crafted message due to an infinite recursion. This issue is patched in version 4.1.86.Final. There is no workaround, except using a custom HaProxyMessageDecoder.

CVE-2021-37136

High

2021-10-19

Protected by Waratek

No public exploit

The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocation size used during decompression). All users of Bzip2Decoder are affected. The malicious input can trigger an OOME and so a DoS attack

CVE-2020-7238

High

2020-01-27

No exploit published

No public exploit

Netty 4.1.43.Final allows HTTP Request Smuggling because it mishandles Transfer-Encoding whitespace (such as a [space]Transfer-Encoding:chunked line) and a later Content-Length header. This issue exists because of an incomplete fix for CVE-2019-16869.

CVE-2019-16869

High

2019-09-26

No exploit published

No public exploit

Netty before 4.1.42.Final mishandles whitespace before the colon in HTTP headers (such as a "Transfer-Encoding : chunked" line), which leads to HTTP request smuggling.

CVE-2015-2156

High

2017-10-18

No exploit published

No public exploit

Netty before 3.9.8.Final, 3.10.x before 3.10.3.Final, 4.0.x before 4.0.28.Final, and 4.1.x before 4.1.0.Beta5 and Play Framework 2.x before 2.3.9 might allow remote attackers to bypass the httpOnly flag on cookies and obtain sensitive information by leveraging improper validation of cookie name and value characters.

CVE-2016-4970

High

2017-04-13

No exploit published

No public exploit

handler/ssl/OpenSslEngine.java in Netty 4.0.x before 4.0.37.Final and 4.1.x before 4.1.1.Final allows remote attackers to cause a denial of service (infinite loop).