CVE-2026-34520 | THREATINT

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.

PUBLISHED Reserved 2026-03-30 | Published 2026-04-01 | Updated 2026-04-04 | Assigner GitHub_M

LOW: 2.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U

Problem types

CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Product status

< 3.13.4

affected

References

github.com/...iohttp/security/advisories/GHSA-63hf-3vf5-4wqf

github.com/...ommit/9370b9714a7a56003cacd31a9b4ae16eab109ba4

github.com/aio-libs/aiohttp/releases/tag/v3.13.4

cve.org (CVE-2026-34520)

nvd.nist.gov (CVE-2026-34520)

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