CVE-2026-45301: Open WebUI missing permission check in files API

Executive brief

Open WebUI, a user interface for interacting with large language models, contains a security flaw in its file management system. Any logged-in user can view, download, or delete files uploaded by any other user on the platform, regardless of their permissions. This could lead to the exposure of sensitive private documents or the unauthorized deletion of critical data.

Technical details

A Broken Access Control (CWE-284) vulnerability exists in the 'files/' related API endpoints of Open WebUI. The backend routers and models fail to validate the 'user_id' of the requesting user against the owner of the file, relying solely on a general authentication check. An attacker with a standard user account can use the GET '/api/v1/files/' endpoint to list all files, GET '/api/v1/files/{id}/content' to download them, and DELETE '/api/v1/files/{id}' to remove them. This vulnerability is patched in version 0.3.16.

Affected products

• Open WebUI open-webui <= 0.3.15

Timeline

• 2026-05-08: disclosed
• 2026-05-14: advisory: GitHub Advisory published
• 2026-05-14: patched: Version 0.3.16 released

References

• https://api.github.com/users/vi11ain
• https://github.com/vi11ain
• https://api.github.com/users/vi11ain/gists%7B/gist_id%7D
• https://api.github.com/users/vi11ain/repos
• https://avatars.githubusercontent.com/u/18503035?v=4
• https://api.github.com/users/vi11ain/events%7B/privacy%7D