FileBrowser Quantum's path traversal issue in subtitle handler allows any authenticated user to read arbitrary files

Summary

FileBrowser Quantum is a free, self-hosted, web-based file manager. Prior to version 1.4.3-beta, the `subtitlesHandler` endpoint (`GET /api/media/subtitles`) accepts two user-controlled query parameters: `path` and `name`, both of which are used in filesystem operations without sanitization, creating two independent path traversal vectors. The primary vector is the `path` parameter: it is passed directly to `idx.GetRealPath()` without calling `SanitizeUserPath()`, allowing an attacker to escape the storage root and set `parentDir` to any directory on the host. No existing anchor file is required. The secondary vector is the `name` parameter: it is joined with `parentDir` via `filepath.Join(parentDir, name)` without stripping directory components, allowing traversal relative to any resolved `parentDir`. Any authenticated user (regardless of role or permissions) can exploit either vector to read any text file readable by the server process, including `/etc/passwd`, SSH keys, database credentials, and JWT signing keys. Version 1.4.3-beta patches the issue.

Timeline

1. Jul 20, 2026, 2:20 PM UTCCVE published
2. Jul 20, 2026, 2:51 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Jul 20, 2026, 2:52 PM UTCRecord last updated

Affected versions

• gtsteffaniak filebrowser

  fixed in 1.4.3-beta

• github.com/gtsteffaniak/filebrowser/backendGo

  fixed in 0.0.0-20260608182036-f3f4bbe80cb5

References 2