4.8
CVSS V3
In aiohttp, compressed files as symlinks are not protected from path traversal
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.
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.
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.
