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CVE-2026-128128 AIOHTTP: WebSocket max_msg_size bypass via integer overflow

7.5 high

High (7.5) in aio-libs aiohttp.

On this page
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.

Severity

CVSS 3.1

7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-770 Allocation of Resources Without Limits or Throttling
Published
Modified
Assigned by
GitHub_M (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
aio-libs aiohttp< 3.14.4

Attack patterns (CAPEC)

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-770 (20).

References

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