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OpenAdvisories
High · 8.7 CVE-2026-123817 EUVD-2026-120454

AIOHTTP WebSocket frame reassembly permits excessive memory consumption from tiny reads

Published Nov 9, 2026 · Updated Nov 14, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
aio-libs aiohttp < 3.14.4 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 python-aiohttp No fix yet —
Debian 13 python-aiohttp No fix yet —
Debian 12 python-aiohttp No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 python-aiohttp No fix yet —
Show 6 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 26.04 LTS python-aiohttp No fix yet —
Ubuntu Pro 24.04 LTS python-aiohttp No fix yet —
Ubuntu Pro 22.04 LTS python-aiohttp No fix yet —
Ubuntu Pro 20.04 LTS python-aiohttp No fix yet —
Ubuntu Pro 18.04 LTS python-aiohttp No fix yet —
Ubuntu Pro 16.04 LTS python-aiohttp No fix yet —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling dask-kubernetes 2026.3.0-r18 —
Wolfi rolling kserve-storage-controller 0.21.0-r9 —
Wolfi rolling open-webui 0.12.3-r3 —

References