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Vulnerability · Published Sep 15, 2026 · Assigned by GitHub_M

CVE-2026-69214Http4s: CookieJar middleware accepts arbitrary Set-Cookie domain

Medium 6.8

In plain English

A medium-severity session fixation in http4s from http4s. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.8Medium
Exploit odds (30 days)0.4%top 66.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.http4s:http4s-client_2.120.23.35GHSA-wv64-j4fq-5f9x
Mavenorg.http4s:http4s-client_2.130.23.35GHSA-wv64-j4fq-5f9x
Mavenorg.http4s:http4s-client_2.131.0.0-M47GHSA-wv64-j4fq-5f9x
Mavenorg.http4s:http4s-client_31.0.0-M47GHSA-wv64-j4fq-5f9x
Mavenorg.http4s:http4s-client_30.23.35GHSA-wv64-j4fq-5f9x

Affected products (as reported)

VendorProductVersions
http4s http4s < 0.23.35>= 1.0.0-M1, < 1.0.0-M47

Weakness: CWE-384, CWE-565 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

References