AIKIDO-2026-10402

TL;DR

The static file server follows symlinks when serving files; a symlink inside the mounted directory that points outside the mount can be used to read arbitrary files (directory traversal). The library also did not provide a dedicated filename sanitizer for multipart uploads—applications that write uploaded files using the client-supplied filename without sanitization can write outside the intended directory. In this fix the static file server resolves paths and returns 403 when the resolved path is outside the mount, and sanitize_filename() was added so multipart handlers can safely derive a basename from untrusted filenames.