AIOHTTP: WebSocket client accepts compressed frames without negotiated permessage-deflate
### Summary The client accepts and decompresses frames with the RSV1 bit set even when the `permessage-deflate` extension was not negotiated. ### Impact A client may unexpectedly decompress WebSocket frames when explicitly opted out. This could lead to additional CPU/memory consumption, but is unlikely to be a significant issue unless a zip bomb vulnerability or similar is also present. --- Patch: https://github.com/aio-libs/aiohttp/commit/47fb6ae354d4fa22048f4dbe7dbf82b625f0a2f6
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-59881US | — | — | ||
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 whe… | ||||
references
External citations — patches, advisories, analysis.
- http://github.com/aio-libs/aiohttp/releases/tag/v3.14.2WEB
- https://github.com/aio-libs/aiohttpPACKAGE
- https://github.com/aio-libs/aiohttp/commit/47fb6ae354d4fa22048f4dbe7dbf82b625f0a2f6WEB
- https://github.com/aio-libs/aiohttp/pull/12978WEB
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mq44-7p77-q5h7WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-59881ADVISORY
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