CVE-2026-34520

CRITICAL

9.1

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, the C parser (the default for most installs) accepted null bytes and control characters in response headers. This issue has been patched in version 3.13.4.

CVE Details

CVSS v3.1 Score9.1

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published4/1/2026

Last Modified4/4/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-113

References

https://github.com/aio-libs/aiohttp/commit/9370b9714a7a56003cacd31a9b4ae16eab109ba4(security-advisories@github.com)

https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4(security-advisories@github.com)

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-63hf-3vf5-4wqf(security-advisories@github.com)

IOC Correlations

No correlations recorded

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