CVE-2026-123817 PUBLISHED

AIOHTTP WebSocket frame reassembly permits excessive memory consumption from tiny reads

Assigner: GitHub_M
Reserved: 06.11.2026 Published: 09.11.2026 Updated: 09.11.2026

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the WebSocket reader retains one bytes object for each transport read while reassembling an incomplete frame. A malicious peer can split a frame into many tiny reads so per-object overhead substantially exceeds the payload bytes allowed by max_msg_size. The condition affects a server receiving frames from a malicious client and a client receiving frames from a malicious server, and can cause excessive memory consumption or denial of service. This issue is fixed in version 3.14.4.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Product Status

Vendor aio-libs
Product aiohttp
Versions
  • Version < 3.14.4 is affected

References

Problem Types

  • CWE-770: Allocation of Resources Without Limits or Throttling CWE