CVE-2025-69230: AIOHTTP Vulnerable to Cookie Parser Warning Storm

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-06 · updated 2026-10-11
Weakness: CWE-779

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, reading multiple invalid cookies can lead to a logging storm. If the cookies attribute is accessed in an application, then an attacker may be able to trigger a storm of warning-level logs using a specially crafted Cookie header. This issue is fixed in 3.13.3.

Affected products

aio-libs aiohttp: from 3.12.7 before 3.13.3 — fixed in 3.13.3
Pypi Aiohttp: before 3.13.3; 0.1, 0.10.0, 0.10.1, 0.10.2, 0.11.0, 0.12.0 (+297) — fixed in 3.13.3

How to fix

Upgrade to a fixed version: aio-libs aiohttp 3.13.3; Pypi Aiohttp 3.13.3. Check the vendor advisory for mitigations.

References

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