CVE-2026-34520

9.1 CRITICAL
Published: April 01, 2026 Modified: April 16, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/aio-libs/aiohttp/commit/9370b9714a7a56003cacd31a9b4ae16eab109ba4
Source: security-advisories@github.com
Patch
https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
Source: security-advisories@github.com
Release Notes
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-63hf-3vf5-4wqf
Source: security-advisories@github.com
Patch Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.1 / 10.0
EPSS (Exploit Probability)
0.1%
19th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

CWE-113

Affected Vendors

aiohttp

Related CVEs

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