http4s CVEs · Medium

CVE	Severity	Published▾	Status	Exploitation	Description
CVE-2026-69216	Medium	2026-09-15	No exploit published	No public exploit	Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVE-2026-69215	Medium	2026-09-15	No exploit published	No public exploit	Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware uses unanchored substring checks instead of RFC 6265 domain and path matching when deciding whether to attach a stored cookie. A cookie for example.com can consequently be sent to an attacker-controlled hostname such as evilexample.com when an application using the same jar makes an attacker-influenced outbound request. This exposes session or authentication cookies and can enable hijacking of the application’s outbound sessions. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVE-2026-69214	Medium	2026-09-15	No exploit published	No public exploit	Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware stores a response cookie’s Domain attribute without checking that it domain-matches the host that supplied the cookie or rejecting public suffixes. A malicious or compromised server contacted through the same CookieJar can plant a cookie for another domain, and the jar later sends that cookie to the victim domain, enabling session fixation or overwriting security-sensitive cookies. The patch validates the Set-Cookie domain against the response origin, although public-suffix rejection remains unimplemented. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVE-2026-69206	Medium	2026-09-15	No exploit published	No public exploit	Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, DigestAuth replay protection records lastNc plus one instead of the highest nonce-count value it has accepted. When a legitimate client sends noncontiguous nc values because of parallel or retried requests, the stored counter remains below the accepted maximum, allowing a passive observer to replay a captured Authorization header multiple times. Successful replays execute authenticated requests, including state-changing operations, as the captured user. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVE-2025-59822	Medium	2025-09-23	No exploit published	Proof of concept only	Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypass front-end servers security controls, launch targeted attacks against active users, and poison web caches. A pre-requisite for exploitation involves the web application being deployed behind a reverse-proxy that forwards trailer headers. This issue has been patched in versions 1.0.0-M45 and 0.23.31.

CVE

Severity

Published▾

Status

Exploitation

Description

CVE-2026-69216

Medium

2026-09-15

No exploit published

No public exploit

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVE-2026-69215

Medium

2026-09-15

No exploit published

No public exploit

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware uses unanchored substring checks instead of RFC 6265 domain and path matching when deciding whether to attach a stored cookie. A cookie for example.com can consequently be sent to an attacker-controlled hostname such as evilexample.com when an application using the same jar makes an attacker-influenced outbound request. This exposes session or authentication cookies and can enable hijacking of the application’s outbound sessions. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVE-2026-69214

Medium

2026-09-15

No exploit published

No public exploit

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware stores a response cookie’s Domain attribute without checking that it domain-matches the host that supplied the cookie or rejecting public suffixes. A malicious or compromised server contacted through the same CookieJar can plant a cookie for another domain, and the jar later sends that cookie to the victim domain, enabling session fixation or overwriting security-sensitive cookies. The patch validates the Set-Cookie domain against the response origin, although public-suffix rejection remains unimplemented. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVE-2026-69206

Medium

2026-09-15

No exploit published

No public exploit

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, DigestAuth replay protection records lastNc plus one instead of the highest nonce-count value it has accepted. When a legitimate client sends noncontiguous nc values because of parallel or retried requests, the stored counter remains below the accepted maximum, allowing a passive observer to replay a captured Authorization header multiple times. Successful replays execute authenticated requests, including state-changing operations, as the captured user. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVE-2025-59822

Medium

2025-09-23

No exploit published

Proof of concept only

Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypass front-end servers security controls, launch targeted attacks against active users, and poison web caches. A pre-requisite for exploitation involves the web application being deployed behind a reverse-proxy that forwards trailer headers. This issue has been patched in versions 1.0.0-M45 and 0.23.31.