Authorization bypass through user-controlled key in Open WebUI - #VU131122

Detailed vulnerability description

The vulnerability allows a remote user to read, modify, and delete arbitrary files owned by other users.

The vulnerability exists due to improper access control in has_access_to_file() in backend/open_webui/routers/files.py when handling file access requests for files referenced by shared chats. A remote user can send crafted requests to file endpoints using a valid file UUID to read, modify, and delete arbitrary files owned by other users.

User interaction is required because the target file must be referenced in a shared chat, and file UUIDs may be disclosed to users with read access to a knowledge base via GET /api/v1/knowledge/{id}/files.

Remediation

Sources

• https://github.com/open-webui/open-webui/security/advisories/GHSA-26g9-27vm-x3q8
• https://github.com/open-webui/open-webui/commit/2e52ad8ff2f8d9ed9f38f76e9bc19c8f92d91fc3