CVE-2026-34517CWE-770

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

Low · published April 1, 2026

CVSS v4.0
2.7
EPSS
1%
Percentile
42.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
2.7 · LOW
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
EPSS
0.00507 · 42.3th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-04-01T20:14Z
EPSS history
Timeline
  • 01 APR 20:14Z
    AIOHTTP: Late size enforcement for non-file multipart fields causes memory DoS
    cvelistv5