CVE-2024-42367 is a medium-severity (CVSS 4.8) CWE-61 vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.
In aiohttp, compressed files as symlinks are not protected from path traversal
Exploitation Status
No confirmed exploitation observed yet
- 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-2024-42367.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
Summary
Static routes which contain files with compressed variants (.gz or .br extension) were vulnerable to path traversal outside the root directory if those variants are symbolic links.
Details
The server protects static routes from path traversal outside the root directory when follow_symlinks=False (default). It does this by resolving the requested URL to an absolute path and then checking that path relative to the root. However, these checks are not performed when looking for compressed variants in the FileResponse class, and symbolic links are then automatically followed when performing Path.stat() and Path.open() to send the file.
Impact
Servers with static routes that contain compressed variants as symbolic links, pointing outside the root directory, or that permit users to upload or create such links, are impacted.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | aiohttp | ≥ 3.10.0b1&&< 3.10.2 | 3.10.2pip install --upgrade 'aiohttp==3.10.2' |
Affected Products
aiohttpaiohttpDetection & 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 3.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-42367 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2024-42367 in your dependencies?
Find it across PyPI, including transitive dependencies.