What’s Vulnerable › Vulnerabilities

CVE-2024-42367: In aiohttp, compressed files as symlinks are not protected from path traversal

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-08-12 · updated 2026-06-17
• Weakness: CWE-61

Description

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. In versions on the 3.10 branch prior to version 3.10.2, static routes which contain files with compressed variants (`.gz` or `.br` extension) are vulnerable to path traversal outside the root directory if those variants are symbolic links. 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 the `Path.stat()` and `Path.open()` to send the file. Version 3.10.2 contains a patch for the issue.

Affected products

• aio-libs aiohttp: from 3.10.0 before 3.10.2 — fixed in 3.10.2

How to fix

Upgrade to a fixed version: aio-libs aiohttp 3.10.2. Check the vendor advisory for mitigations.

References

• https://github.com/aio-libs/aiohttp/blob/e0ff5246e1d29b7710ab1a2bbc972b48169f1c05/aiohttp/web_fileresponse.py#L177
• https://github.com/aio-libs/aiohttp/blob/e0ff5246e1d29b7710ab1a2bbc972b48169f1c05/aiohttp/web_urldispatcher.py#L674
• https://github.com/aio-libs/aiohttp/commit/ce2e9758814527589b10759a20783fb03b98339f
• https://github.com/aio-libs/aiohttp/pull/8653
• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jwhx-xcg6-8xhj

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