Vulnerability · Published Oct 19, 2026 · Assigned by GitHub_M

CVE-2026-111750AIOHTTP: Pure-Python parser request smuggling

Medium 6.3

In plain English

A medium-severity security flaw in aiohttp from aio-libs. 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 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.3Medium

Exploit odds (30 days)0.4%top 67.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	python-aiohttp	no fix listed	DEBIAN-CVE-2026-111750
Debian:13	python-aiohttp	no fix listed	DEBIAN-CVE-2026-111750
Debian:14	python-aiohttp	no fix listed	DEBIAN-CVE-2026-111750
PyPI	aiohttp	3.14.4	GHSA-pqxq-w44r-73xw
Ubuntu:26.10	python-aiohttp	no fix listed	UBUNTU-CVE-2026-111750

Affected products (as reported)

Vendor	Product	Versions
aio-libs	aiohttp	< 3.14.4

Weakness: CWE-444 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L

References

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-pqxq-w44r-73xw x_refsource_CONFIRM
https://github.com/aio-libs/aiohttp/commit/9b27347e61454d9f8ca2055f4c67a37dee336e83 x_refsource_MISC
https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4 x_refsource_MISC