CVE-2026-50269

Name	CVE-2026-50269
Description	AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request. This vulnerability is fixed in 3.14.0.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-aiohttp (PTS)	bullseye	3.7.4-1	vulnerable
	bullseye (security)	3.7.4-1+deb11u2	vulnerable
	bookworm, bookworm (security)	3.8.4-1+deb12u1	vulnerable
	trixie (security), trixie	3.11.16-1+deb13u1	vulnerable
	forky, sid	3.14.1-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-aiohttp	source	(unstable)	3.14.0-1

Notes

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m6qw-4cw2-hm4m
Fixed by: https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8 (v3.14.0)