CVE-2025-53643

Name	CVE-2025-53643
Description	AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.12.14, the Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request. If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections. Version 3.12.14 contains a patch for this issue.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1109336

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+deb11u1	vulnerable
	bookworm, bookworm (security)	3.8.4-1+deb12u1	vulnerable
	forky, sid, trixie	3.11.16-1	vulnerable

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)	(unfixed)			1109336

Notes

[trixie] - python-aiohttp <no-dsa> (Minor issue)
[bookworm] - python-aiohttp <no-dsa> (Minor issue)
[bullseye] - python-aiohttp <postponed> (Minor issue; request smuggling)
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-9548-qrrj-x5pj
https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a (v3.12.14)