Medium 6.3Published Aug 3, 2026

CVE-2026-69243AIOHTTP: HTTP request smuggling via WebSocket upgrade

Updated under an hour ago (Oct 26, 2026, 6:40 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for aio-libs aiohttp

Exploited in the last 30 days

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the HTTP parsers were vulnerable to a request smuggling attack relating to WebSocket upgrades. If using the server-side component, an attacker may be able to execute a request smuggling vulnerability using an edge case in the WebSocket upgrade procedure. A WebSocket upgrade request with a body could cause the parser to switch protocols before the complete request body was received, leaving trailing bytes to be handled as upgraded-protocol or pipelined data rather than normal HTTP body data. This issue is fixed in version 3.14.2.

CVSS: 6.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-444
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Undergoing Analysis
Record last updated: Aug 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

aio-libs aiohttp aio_libs:aiohttp (from the name)	before 3.14.2	CNA record

References

References

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mfx4-hv73-q22v	x-refsource-confirm
https://github.com/aio-libs/aiohttp/pull/13017	x-refsource-misc
https://github.com/aio-libs/aiohttp/commit/6ae358f0983c3f4d6f67692b2f8e65dc8e091c98	x-refsource-misc
https://github.com/aio-libs/aiohttp/releases/tag/v3.14.2	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.