Fluid Attacks Database

Description

AIOHTTP has a Multipart Header Size Bypass

Summary

A response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability.

Impact

Multipart headers were not subject to the same size restrictions in place for normal headers, potentially allowing substantially more data to be loaded into memory than intended. However, other restrictions in place limit the impact of this vulnerability.

Patch: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f

Mitigation

Update Impact

Minimal update. May introduce new vulnerabilities or breaking changes.

Ecosystem	Component	Affected version	Patched versions
pypi	aiohttp	>=0 <3.13.4	3.13.4
debian 12	python-aiohttp	=3.10.0-1 \|\| =3.10.1-1 \|\| =3.10.10-1 \|\| =3.10.10-2 \|\| =3.10.11-1 \|\| =3.10.3-1 \|\| =3.10.3-2 \|\| =3.10.3-3 \|\| =3.10.4-1 \|\| =3.10.5-1 \|\| =3.10.6-1 \|\| =3.10.8-1 \|\| =3.11.15-1 \|\| =3.11.16-1 \|\| =3.12.15-1 \|\| =3.13.0-1 \|\| =3.13.1-1 \|\| =3.13.3-1 \|\| =3.13.3-2 \|\| =3.13.3-3 \|\| =3.13.5-1 \|\| =3.14.0-1 \|\| =3.14.1-1 \|\| =3.14.1-2 \|\| =3.14.1-3 \|\| =3.14.1-4 \|\| =3.14.1-5 \|\| =3.14.3-1 \|\| =3.8.4-1 \|\| =3.8.4-1+deb12u1 \|\| =3.8.5-1 \|\| =3.8.6-1 \|\| =3.9.1-1 \|\| =3.9.5-1	-
debian 13	python-aiohttp	=3.11.16-1 \|\| =3.11.16-1+deb13u1 \|\| =3.12.15-1 \|\| =3.13.0-1 \|\| =3.13.1-1 \|\| =3.13.3-1 \|\| =3.13.3-2 \|\| =3.13.3-3 \|\| =3.13.5-1 \|\| =3.14.0-1 \|\| =3.14.1-1 \|\| =3.14.1-2 \|\| =3.14.1-3 \|\| =3.14.1-4 \|\| =3.14.1-5 \|\| =3.14.3-1	-
debian 14	python-aiohttp	=3.11.16-1 \|\| =3.12.15-1 \|\| =3.13.0-1 \|\| =3.13.1-1 \|\| =3.13.3-1 \|\| =3.13.3-2 \|\| =3.13.3-3 \|\| >=0 <3.13.5-1	3.13.5-1

Aliases

1. CVE-2026-345162. NVD-2026-345163. OSV-2026-345164. OSV-DEBIAN-2026-345165. GHSA-m5qp-6w8w-w6476. GCVE-2026-345167. SECURITY-TRACKER-CVE-2026-34516

References

1. https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m5qp-6w8w-w6472. https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f3. https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4

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