CVE-2026-34516

HIGH 7.5

AIOHTTP: Multipart Header Size Bypass

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

12th

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.

CWE	CWE-770
Vendor	aio-libs
Product	aiohttp
Published	Apr 1, 2026
Last Updated	Apr 4, 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-m5qp-6w8w-w647 github.com: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f github.com: https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4