CVE-2026-34525

UNKNOWN 0.0

AIOHTTP: Duplicate Host header accepted

CVSS Score

0.0

EPSS Score

0.1%

EPSS Percentile

25th

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, multiple Host headers were allowed in aiohttp. This issue has been patched in version 3.13.4.

CWE	CWE-20 CWE-444
Vendor	aio-libs
Product	aiohttp
Published	Apr 1, 2026
Last Updated	Apr 2, 2026

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Affected Versions

aio-libs / aiohttp

< 3.13.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/aio-libs/aiohttp/security/advisories/GHSA-c427-h43c-vf67 github.com: https://github.com/aio-libs/aiohttp/commit/53e2e6fc58b89c6185be7820bd2c9f40216b3000 github.com: https://github.com/aio-libs/aiohttp/commit/e00ca3cca92c465c7913c4beb763a72da9ed8349 github.com: https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4