CVE-2026-128128

CVSS 7.5 (high) · published 2026-11-13

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the C WebSocket reader adds a declared frame length to the size of an already buffered partial message using signed 64-bit arithmetic. A length near two to the power of 63 can overflow, allowing the max_msg_size check to pass. A remote peer can send a small non-final fragment followed by an oversized message and cause unbounded memory consumption. The Python WebSocket reader is unaffected. This issue is fixed in version 3.14.4.

Weakness: CWE-770

Source: NVD CVE-2026-128128

References

• https://github.com/aio-libs/aiohttp/commit/8c8906a19f64e52ef6a7d44d65217eb3c5af413f
• https://github.com/aio-libs/aiohttp/commit/8cfbe9abe5e11b84006a10f9bdf82bf607671dab
• https://github.com/aio-libs/aiohttp/pull/13415
• https://github.com/aio-libs/aiohttp/pull/13494
• https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4
• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-3rp8-rxj8-mvjw

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