CVE-2026-34517

MEDIUM

AIOHTTP: Late size enforcement for non-file multipart fields causes memory DoS

Title source: cna

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.

References (3)

Scores

CVSS v3 5.3
EPSS 0.0005
EPSS Percentile 15.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-770
Status published
Products (3)
aiohttp/aiohttp < 3.13.4
aio-libs/aiohttp < 3.13.4
pypi/aiohttp 0 - 3.13.4PyPI
Published Apr 01, 2026
Tracked Since Apr 02, 2026