CVE-2024-52303 — aiohttp
Fix: aio-libs/aiohttp@bc15db6CVE-2024-52303 is a CWE-772 vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.
aiohttp memory leak when middleware is enabled when requesting a resource with a non-allowed method
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-52303.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
aiohttpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | aiohttp | ≥ 3.10.6&&< 3.10.11 | 3.10.11pip install --upgrade 'aiohttp==3.10.11' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aiohttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aiohttp to 3.10.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-52303 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-52303 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-52303. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-52303 in your dependencies?
O3 Security finds CVE-2024-52303 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.