PYSEC-2026-1106
AIOHTTP vulnerable to DoS through chunked messages
Quick fix
PYSEC-2026-1106 — aiohttp: upgrade to the fixed version with the command below.
pip install --upgrade 'aiohttp>=3.13.3'Details
### Summary
Handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks.
### Impact
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.
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Patch: https://github.com/aio-libs/aiohttp/commit/dc3170b56904bdf814228fae70a5501a42a6c712 Patch: https://github.com/aio-libs/aiohttp/commit/4ed97a4e46eaf61bd0f05063245f613469700229
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-g84x-mcqj-x9qq[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2025-69229[ADVISORY]
- https://github.com/aio-libs/aiohttp/commit/4ed97a4e46eaf61bd0f05063245f613469700229[WEB]
- https://github.com/aio-libs/aiohttp/commit/dc3170b56904bdf814228fae70a5501a42a6c712[WEB]
- https://github.com/aio-libs/aiohttp[PACKAGE]
- https://pypi.org/project/aiohttp[PACKAGE]
- https://github.com/advisories/GHSA-g84x-mcqj-x9qq[ADVISORY]