medium6.9
CVE-2026-59881
AIOHTTP: WebSocket client accepts compressed frames without negotiated permessage-deflate
Impact
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the WebSocket client accepts and decompresses frames with the RSV1 bit set even when the permessage-deflate extension was not negotiated, allowing a malicious server to cause unexpected CPU and memory consumption. This issue is fixed in version 3.14.2.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | aiohttp | <= 3.14.1 | 3.14.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-mq44-7p77-q5h7
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mq44-7p77-q5h7
- https://nvd.nist.gov/vuln/detail/CVE-2026-59881
- https://github.com/aio-libs/aiohttp/pull/12978
- https://github.com/aio-libs/aiohttp/commit/47fb6ae354d4fa22048f4dbe7dbf82b625f0a2f6
- http://github.com/aio-libs/aiohttp/releases/tag/v3.14.2