langflow has Unauthenticated IDOR on Image Downloads

Summary

The /api/v1/files/images/{flow_id}/{file_name} endpoint serves image files without any authentication or ownership check. Any unauthenticated request with a known flow_id and file_name returns the image with HTTP 200.

Details

src/backend/base/langflow/api/v1/files.py:138-164 — download_image takes flow_id: UUID as a bare path parameter with no Depends(get_flow) or CurrentActiveUser. All other file routes (download_file, upload_file, list_files, delete_file) use Depends(get_flow) which enforces both authentication and ownership. There is no global auth middleware on /api/v1; protection is per-endpoint only.

PoC

curl -v "http://localhost:7860/api/v1/files/images/<flow_uuid>/<filename.png>"
# Returns HTTP 200 with image bytes, no auth header required

Impact

Unauthenticated cross-tenant data leak. In a multi-tenant deployment, any attacker who can discover or guess a flow_id (UUIDs can be leaked through other API responses) can download any user's uploaded images without credentials.