`CVE-2021-21409` Netty

Affected software	Netty
Severity	5.9 Medium CVSS 3.1 3 scores
Fixed in	`4.1.61.Final`
Weakness	CWE-444
Published	30 Mar 2021
Updated	8 Oct 2026

Description

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty (io.netty:netty-codec-http2) before version 4.1.61.Final there is a vulnerability that enables request smuggling. The content-length header is not correctly validated if the request only uses a single Http2HeaderFrame with the endStream set to to true. This could lead to request smuggling if the request is proxied to a remote peer and translated to HTTP/1.1. This is a followup of GHSA-wm47-8v5p-wjpj/CVE-2021-21295 which did miss to fix this one case. This was fixed as part of 4.1.61.Final.

Exploitation status

No public exploit

No exploit has been reported in the sources we check. Published 5 years ago.

CISA KEV not listed
VulnCheck KEV not listed
CISA Vulnrichment exploitation: none
Indexed PoC none indexed
EPSS 4.9% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

A public code fix exists: netty/netty b0fa4d5.

Protection none
Action unverified
Review automated Upstream data
Record active

Decided by	Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all
Finding	This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.
Candidate fix	https://github.com/netty/netty/commit/b0fa4d5aab4215f3c22ce6123dd8dd5f38dc0432 : a commit: the change itself

Decided by

Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

Finding

This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.

Candidate fix

https://github.com/netty/netty/commit/b0fa4d5aab4215f3c22ce6123dd8dd5f38dc0432 : a commit: the change itself

CVSS

5.9 MEDIUM v3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

Version Score Band Vector Assigner Type

CVSS 3.1 5.9 MEDIUM CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N security-advisories@github.com Secondary published

CVSS 3.1 5.9 MEDIUM CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N NVD Primary

CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:N/I:P/A:N NVD Primary

Version	Score	Band	Vector	Assigner	Type
CVSS 3.1	5.9	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`	security-advisories@github.com	Secondary	published
CVSS 3.1	5.9	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`	NVD	Primary
CVSS 2.0	4.3	none	`AV:N/AC:M/Au:N/C:N/I:P/A:N`	NVD	Primary

Affected software and releases

Oracle advisories

Advisory	Type	Quarter	Products Oracle names in its risk matrix
Oracle Critical Patch Update April 2022 ↗	CPU	2022-Q2	Oracle Communications / Policy (Netty) (1.14.0)
Oracle Critical Patch Update January 2022 ↗	CPU	2022-Q1	Oracle Communications / Console (Netty) (1.7.0) Oracle NoSQL Database / Administration (Netty) (Prior to 21.1.12)
Oracle Critical Patch Update October 2021 ↗	CPU	2021-Q4	Oracle Communications Applications / Multiplexor (Netty) (8.1) Oracle Communications Applications / OUI Installer (Netty) (12.0.0.3) Oracle Communications Applications / PSR Designer (Netty) (7.4.2) Oracle Financial Services Applications / Collateral Review (Netty) (14.2, 14.3, 14.5) Oracle Financial Services Applications / Dashboard (Netty) (14.2, 14.3, 14.5) Oracle Financial Services Applications / Lending (Netty) (14.2, 14.3, 14.5)
Oracle Critical Patch Update July 2021 ↗	CPU	2021-Q3	Oracle Construction and Engineering / Admin (Netty) (17.12.0-17.12.11, 18.8.0-18.8.11, 19.12.0-19.12.10)

Advisory

Type

Quarter

Products Oracle names in its risk matrix

Oracle Critical Patch Update April 2022 ↗

CPU

2022-Q2

Oracle Communications / Policy (Netty) (1.14.0)

Oracle Critical Patch Update January 2022 ↗

CPU

2022-Q1

Oracle Communications / Console (Netty) (1.7.0)
Oracle NoSQL Database / Administration (Netty) (Prior to 21.1.12)

Oracle Critical Patch Update October 2021 ↗

CPU

2021-Q4

Oracle Communications Applications / Multiplexor (Netty) (8.1)
Oracle Communications Applications / OUI Installer (Netty) (12.0.0.3)
Oracle Communications Applications / PSR Designer (Netty) (7.4.2)
Oracle Financial Services Applications / Collateral Review (Netty) (14.2, 14.3, 14.5)
Oracle Financial Services Applications / Dashboard (Netty) (14.2, 14.3, 14.5)
Oracle Financial Services Applications / Lending (Netty) (14.2, 14.3, 14.5)

Oracle Critical Patch Update July 2021 ↗

CPU

2021-Q3

Oracle Construction and Engineering / Admin (Netty) (17.12.0-17.12.11, 18.8.0-18.8.11, 19.12.0-19.12.10)

Oracle components and versions

Family	Component	Versions, as Oracle lists them	Read as
Oracle Communications	Console (Netty)	1.7.0	1.7.0
Oracle Communications	Policy (Netty)	1.14.0	1.14.0
Oracle Communications Applications	Multiplexor (Netty)	8.1	8.1
Oracle Communications Applications	OUI Installer (Netty)	12.0.0.3	12.0.0.3
Oracle Communications Applications	PSR Designer (Netty)	7.4.2	7.4.2
Oracle Construction and Engineering	Admin (Netty)	17.12.0-17.12.11, 18.8.0-18.8.11, 19.12.0-19.12.10
Oracle Financial Services Applications	Collateral Review (Netty)	14.2, 14.3, 14.5	14.2 · 14.3 · 14.5
Oracle Financial Services Applications	Dashboard (Netty)	14.2, 14.3, 14.5	14.2 · 14.3 · 14.5
Oracle Financial Services Applications	Lending (Netty)	14.2, 14.3, 14.5	14.2 · 14.3 · 14.5
Oracle NoSQL Database	Administration (Netty)	Prior to 21.1.12

Family

Component

Versions, as Oracle lists them

Read as

Oracle Communications

Console (Netty)

1.7.0

Oracle Communications

Policy (Netty)

1.14.0

Oracle Communications Applications

Multiplexor (Netty)

8.1

Oracle Communications Applications

OUI Installer (Netty)

12.0.0.3

Oracle Communications Applications

PSR Designer (Netty)

7.4.2

Oracle Construction and Engineering

Admin (Netty)

17.12.0-17.12.11, 18.8.0-18.8.11, 19.12.0-19.12.10

Oracle Financial Services Applications

Collateral Review (Netty)

14.2, 14.3, 14.5

14.2 · 14.3 · 14.5

Oracle Financial Services Applications

Dashboard (Netty)

14.2, 14.3, 14.5

14.2 · 14.3 · 14.5

Oracle Financial Services Applications

Lending (Netty)

14.2, 14.3, 14.5

14.2 · 14.3 · 14.5

Oracle NoSQL Database

Administration (Netty)

Prior to 21.1.12

Maven packages

Affected and fixed versions, from OSV.dev

Package Introduced Fixed Last affected

io.netty:netty-codec-http2 4.0.0 4.1.61.Final unbounded

org.jboss.netty:netty 0 none unbounded

io.netty:netty 0 none unbounded

Package	Introduced	Fixed	Last affected
`io.netty:netty-codec-http2`	4.0.0	`4.1.61.Final`	unbounded
`org.jboss.netty:netty`	0	none	unbounded
`io.netty:netty`	0	none	unbounded

Products and versions

21 products, 31 version entries

Source	Vendor	Product	Scheme	Affected versions
nvd	debian	debian linux	generic	10.0
osv	io.netty	netty	generic	any version
osv	io.netty	netty-codec-http2	generic	≥ 4.0.0 and ＜ 4.1.61
nvd	netapp	oncommand api services	generic	any version
nvd	netapp	oncommand workflow automation	generic	any version
nvd	netty	netty	generic	＜ 4.1.61
nvd	oracle	banking corporate lending process management	generic	14.2.0 · 14.3.0 · 14.5.0
nvd	oracle	banking credit facilities process management	generic	14.2.0 · 14.3.0 · 14.5.0
nvd	oracle	banking trade finance process management	generic	14.2.0 · 14.3.0 · 14.5.0
nvd	oracle	coherence	generic	12.2.1.4.0 · 14.1.1.0.0
nvd	oracle	communications brm - elastic charging engine	generic	12.0.0.3
nvd	oracle	communications cloud native core console	generic	1.7.0
nvd	oracle	communications cloud native core policy	generic	1.14.0
nvd	oracle	communications design studio	generic	7.4.2.0.0
nvd	oracle	communications messaging server	generic	8.1
nvd	oracle	helidon	generic	1.4.10 · 2.4.0
nvd	oracle	jd edwards enterpriseone tools	generic	＜ 9.2.6.3
nvd	oracle	nosql database	generic	＜ 21.1.12
nvd	oracle	primavera gateway	generic	≥ 17.12.0 and ≤ 17.12.11 · ≥ 18.8.0 and ≤ 18.8.11 · ≥ 19.12.0 and ≤ 19.12.10
osv	org.jboss.netty	netty	generic	any version
nvd	quarkus	quarkus	generic	≤ 1.13.7

Source

Vendor

Product

Scheme

Affected versions

nvd

debian

debian linux

generic

10.0

osv

io.netty

netty

generic

any version

osv

io.netty

netty-codec-http2

generic

≥ 4.0.0 and ＜ 4.1.61

nvd

netapp

oncommand api services

generic

any version

nvd

netapp

oncommand workflow automation

generic

any version

nvd

netty

generic

＜ 4.1.61

nvd

oracle

banking corporate lending process management

generic

14.2.0 · 14.3.0 · 14.5.0

nvd

oracle

banking credit facilities process management

generic

14.2.0 · 14.3.0 · 14.5.0

nvd

oracle

banking trade finance process management

generic

14.2.0 · 14.3.0 · 14.5.0

nvd

oracle

coherence

generic

12.2.1.4.0 · 14.1.1.0.0

nvd

oracle

communications brm - elastic charging engine

generic

12.0.0.3

nvd

oracle

communications cloud native core console

generic

1.7.0

nvd

oracle

communications cloud native core policy

generic

1.14.0

nvd

oracle

communications design studio

generic

7.4.2.0.0

nvd

oracle

communications messaging server

generic

8.1

nvd

oracle

helidon

generic

1.4.10 · 2.4.0

nvd

oracle

jd edwards enterpriseone tools

generic

＜ 9.2.6.3

nvd

oracle

nosql database

generic

＜ 21.1.12

nvd

oracle

primavera gateway

generic

≥ 17.12.0 and ≤ 17.12.11 · ≥ 18.8.0 and ≤ 18.8.11 · ≥ 19.12.0 and ≤ 19.12.10

osv

org.jboss.netty

netty

generic

any version

nvd

quarkus

generic

≤ 1.13.7

References

URL	Tags
https://github.com/netty/netty/commit/b0fa4d5aab4215f3c22ce6123dd8dd5f38dc0432	commit
https://github.com/netty/netty/security/advisories/GHSA-f256-j965-7f32	WEB
https://github.com/netty/netty/security/advisories/GHSA-wm47-8v5p-wjpj	WEB
https://lists.apache.org/thread.html/re39391adcb863f0e9f3f15e7986255948f263f02e4700b82453e7102@%3Cissues.zookeeper.apache.org%3E	WEB
https://lists.apache.org/thread.html/re1911e05c08f3ec2bab85744d788773519a0afb27272a31ac2a0b4e8@%3Cnotifications.zookeeper.apache.org%3E	WEB
https://lists.apache.org/thread.html/rdd5715f3ee5e3216d5e0083a07994f67da6dbb9731ce9e7a6389b18e@%3Ccommits.zookeeper.apache.org%3E	WEB
https://lists.apache.org/thread.html/rdd206d9dd7eb894cc089b37fe6edde2932de88d63a6d8368b44f5101@%3Ccommits.zookeeper.apache.org%3E	WEB
https://lists.apache.org/thread.html/rd8f72411fb75b98d366400ae789966373b5c3eb3f511e717caf3e49e@%3Cissues.flink.apache.org%3E	WEB
https://lists.apache.org/thread.html/rd4a6b7dec38ea6cd28b6f94bd4b312629a52b80be3786d5fb0e474bc@%3Cissues.kudu.apache.org%3E	WEB
https://lists.apache.org/thread.html/rcae42fba06979934208bbd515584b241d3ad01d1bb8b063512644362@%3Cdev.zookeeper.apache.org%3E	WEB

URL

Timeline

Published	2021-03-30	By the CVE Program.
NVD record modified	2026-10-08	NVD's own last-modified date for this record.

Published

2021-03-30

By the CVE Program.

NVD record modified

2026-10-08

NVD's own last-modified date for this record.

How VRT decided (17 of 24 rules ran)

17 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file no match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no match An ARMR security-rule template on disk for this CVE

4 manual-classification no match A researcher's recorded decision for this specific CVE

5 manual classification no match Manual classification of this CVE in the legacy dataset

6 non-java-upstream no match A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component no match The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side no match Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven matched In scope Maven packages: io.netty:netty-codec-http2, org.jboss.netty:netty, io.netty:netty

10 cna-maven-package not reached An affected Maven artifact named by the CNA itself

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint matched Mitigation candidate References include candidate fix URL (commit tier): https://github.com/netty/netty/commit/b0fa4d5aab4215f3c22ce6123dd8dd5f38dc0432

18 open-source-maven skipped The affected package being open source on Maven, so the fix can be read

19 poc-derivable skipped An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit skipped Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

21 secure-rule-match no match A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc skipped Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold withheld CVE ships in Oracle Critical Patch Update April 2022, Oracle Critical Patch Update January 2022, Oracle Critical Patch Update October 2021, Oracle Critical Patch Update July 2021 (CPU) — Oracle treats it as urgent, so severity does not settle it

24 no-exploit-published decided it matched No exploit published No exploit code has been published, and an upstream fix path does exist, so the remediation half of the candidacy still holds.

Products the scope rules checked

The products this CVE's record names, and whether VRT tracks each one. The scope rules decided on these.

Vendor Product Tracked CPE Source

netty netty tracked cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* yaml

debian debian_linux not tracked cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

netapp oncommand_api_services not tracked cpe:2.3:a:netapp:oncommand_api_services:-:*:*:*:*:*:*:*

netapp oncommand_workflow_automation not tracked cpe:2.3:a:netapp:oncommand_workflow_automation:-:*:*:*:*:*:*:*

oracle banking_corporate_lending_process_management tracked cpe:2.3:a:oracle:banking_corporate_lending_process_management:14.2.0:*:*:*:*:*:*:* yaml

oracle banking_credit_facilities_process_management tracked cpe:2.3:a:oracle:banking_credit_facilities_process_management:14.2.0:*:*:*:*:*:*:* yaml

oracle banking_trade_finance_process_management tracked cpe:2.3:a:oracle:banking_trade_finance_process_management:14.2.0:*:*:*:*:*:*:* yaml

oracle coherence tracked cpe:2.3:a:oracle:coherence:12.2.1.4.0:*:*:*:*:*:*:* yaml

oracle communications_brm_-_elastic_charging_engine tracked cpe:2.3:a:oracle:communications_brm_-_elastic_charging_engine:12.0.0.3:*:*:*:*:*:*:* yaml

oracle communications_cloud_native_core_console tracked cpe:2.3:a:oracle:communications_cloud_native_core_console:1.7.0:*:*:*:*:*:*:* yaml

oracle communications_cloud_native_core_policy tracked cpe:2.3:a:oracle:communications_cloud_native_core_policy:1.14.0:*:*:*:*:*:*:* yaml

oracle communications_design_studio tracked cpe:2.3:a:oracle:communications_design_studio:7.4.2.0.0:*:*:*:*:*:*:* yaml

oracle communications_messaging_server tracked cpe:2.3:a:oracle:communications_messaging_server:8.1:*:*:*:*:*:*:* yaml

oracle helidon tracked cpe:2.3:a:oracle:helidon:1.4.10:*:*:*:*:*:*:* yaml

oracle jd_edwards_enterpriseone_tools tracked cpe:2.3:a:oracle:jd_edwards_enterpriseone_tools:*:*:*:*:*:*:*:* yaml

oracle nosql_database tracked cpe:2.3:a:oracle:nosql_database:*:*:*:*:*:*:*:* yaml

oracle primavera_gateway tracked cpe:2.3:a:oracle:primavera_gateway:*:*:*:*:*:*:*:* yaml

quarkus quarkus tracked cpe:2.3:a:quarkus:quarkus:*:*:*:*:*:*:*:* yaml

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