CVE-2024-52303 aiohttp memory leak when middleware is enabled when requesting a resource with a non-allowed method
An attacker can exhaust server memory by sending many requests with non-allowed methods when middleware is enabled, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-52303?
CVE-2024-52303 is a high-severity denial of service vulnerability in aio-libs aiohttp, published on 18 Nov 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. In versions starting with 3.10.6 and prior to 3.10.11, 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. 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. Those who use any middlewares with aiohttp.web should upgrade to version 3.10.11 to receive a patch.
Weakness: CWE-772
Which versions are affected by CVE-2024-52303?
3 open source packages ship an affected version, including aiohttp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
aiohttp PyPI | From 3.10.6 | 3.10.11 |
aiohttp PyPI | From 3.10.6 | 3.10.11 |
aiohttp PyPI | From 3.10.6 | 3.10.11 |
Linux distribution packages (1)
python-aiohttp openSUSE:Tumbleweed | All versions | 3.11.9-1.1 |
Products include Aiohttp Aiohttp.
How do I fix CVE-2024-52303?
Upgrade aiohttp to 3.10.11 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-52303 being exploited?
There is no known exploitation of CVE-2024-52303 in the wild and no public exploit code.
Other vulnerabilities in aio-libs aiohttp
- CVE-2025-69223 AIOHTTP's HTTP Parser auto_decompress feature is vulnerable to zip bomb
- CVE-2024-30251 Denial of service when trying to parse malformed POST requests in aiohttp
- CVE-2023-49081 aiohttp's ClientSession is vulnerable to CRLF injection via version
- CVE-2026-22815 AIOHTTP: Uncapped memory usage possible through aiohttp allowing unlimited trailer headers
- CVE-2026-54273 AIOHTTP: HTTP/1 Pipelined Requests Queue Without Limit
Sources
Also known as CLEANSTART-2026-HK21163, CLEANSTART-2026-PZ91840, DEBIAN-CVE-2024-52303, GHSA-27mf-ghqm-j3j8, PYSEC-2026-1096, openSUSE-SU-2024:14556-1.