id: PYSEC-2026-1096
published: "2026-07-07T14:34:45.010533Z"
modified: "2026-07-07T17:23:35.646669Z"
aliases:
- CVE-2024-52303
- GHSA-27mf-ghqm-j3j8
summary: aiohttp has a memory leak when middleware is enabled when requesting a resource with a non-allowed method
details: "### Summary\n\nA memory leak can occur when a request produces a `MatchInfoError`. This was caused by adding an entry to a cache on each request, due to the building of each `MatchInfoError` producing a unique cache entry.\n\n### Impact\n\nIf the user is making use of any middlewares with `aiohttp.web` then it is advisable to upgrade immediately.\n\nAn attacker may be able to exhaust the memory resources of a server by sending a substantial number (100,000s to millions) of such requests.\n\n-----\n\nPatch: https://github.com/aio-libs/aiohttp/commit/bc15db61615079d1b6327ba42c682f758fa96936"
affected:
- package:
    name: aiohttp
    ecosystem: PyPI
    purl: pkg:pypi/aiohttp
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: 3.10.6
    - fixed: 3.10.11
  versions:
  - 3.10.10
  - 3.10.11rc0
  - 3.10.6
  - 3.10.7
  - 3.10.8
  - 3.10.9
references:
- type: WEB
  url: https://github.com/aio-libs/aiohttp/security/advisories/GHSA-27mf-ghqm-j3j8
- type: ADVISORY
  url: https://nvd.nist.gov/vuln/detail/CVE-2024-52303
- type: FIX
  url: https://github.com/aio-libs/aiohttp/commit/bc15db61615079d1b6327ba42c682f758fa96936
- type: PACKAGE
  url: https://github.com/aio-libs/aiohttp
- type: PACKAGE
  url: https://pypi.org/project/aiohttp
- type: ADVISORY
  url: https://github.com/advisories/GHSA-27mf-ghqm-j3j8
severity:
- type: CVSS_V3
  score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- type: CVSS_V4
  score: 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