AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks. If an application makes use of the request.read() method in an endpoint, it may be possible for an attacker to cause the server to spend a moderate amount of blocking CPU time (e.g. 1 second) while processing the request. This could potentially lead to DoS as the server would be unable to handle other requests during that time. This issue is fixed in version 3.13.3.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/aio-libs/aiohttp/commit/4ed97a4e46eaf61bd0f05063245f613469700229 Patch
- https://github.com/aio-libs/aiohttp/commit/dc3170b56904bdf814228fae70a5501a42a6c712 Patch
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-g84x-mcqj-x9qq Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.6 · aiohttpNVD modified 2026-10-11 20:10
Affected (CPE criteria) 1
cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*