aiohttp has a memory leak when middleware is enabled when requesting a resource with a non-allowed method
Summary
A 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.
Impact
If the user is making use of any middlewares with aiohttp.web then it is advisable to upgrade immediately.
An attacker may be able to exhaust the memory resources of a server by sending a substantial number (100,000s to millions) of such requests.
Patch: https://github.com/aio-libs/aiohttp/commit/bc15db61615079d1b6327ba42c682f758fa96936
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | aiohttp | >= 3.10.6, < 3.10.11 | 3.10.11 |
References
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-27mf-ghqm-j3j8
- https://nvd.nist.gov/vuln/detail/CVE-2024-52303
- https://github.com/aio-libs/aiohttp/commit/bc15db61615079d1b6327ba42c682f758fa96936
- https://github.com/aio-libs/aiohttp
- https://pypi.org/project/aiohttp
- https://github.com/advisories/GHSA-27mf-ghqm-j3j8
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-772- Platform
- Python (PyPI)
- Package
aiohttp- Disclosed
- 18.11.2024
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1096 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-27mf-ghqm-j3j8 - CC BY 4.0
Vulnerability history: aiohttp
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 55
- First → latest
- 02.2021 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 7
- Medium 29
- Low 19
Disclosures per year
- 2021: 1
- 2022: 0
- 2023: 6
- 2024: 7
- 2025: 1
- 2026: 40
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aiohttp has a memory leak when middleware is enabled when requesting a resource with a non-allowed method this entry
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