aio-libs/aiohttp · Security
AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
- GHSA ID
- GHSA-3wq7-rqq7-wx6j
- CVE ID
- CVE-2026-34517
- Severity
- low
- Published
- Updated
- CVSS v4
- 2.7 · 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
Description
Summary
For some multipart form fields, aiohttp read the entire field into memory before checking client_max_size.
Impact
If an application uses Request.post() an attacker can send a specially crafted multipart request to force significant temporary memory allocation even when the request is ultimately rejected.
Patch: https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145
CWEs
- CWE-770 · Allocation of Resources Without Limits or Throttling
References
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-3wq7-rqq7-wx6j ↗
- https://nvd.nist.gov/vuln/detail/CVE-2026-34517 ↗
- https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145 ↗
- https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4 ↗
- https://github.com/advisories/GHSA-3wq7-rqq7-wx6j ↗