Vulnerability Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, multiple endpoints accept a user-supplied file_id and attach the referenced file to a resource the caller controls (folder knowledge, knowledge-base contents) without verifying that the caller owns or has been granted access to the file. The file's content then becomes reachable through the downstream RAG / file-content paths, allowing any authenticated user to exfiltrate any other user's private file — and on the knowledge-base path, also to overwrite it — given knowledge of the file's UUID. This affects backend/open_webui/routers/folders.py (POST /api/v1/folders/{id}/update), backend/open_webui/routers/knowledge.py (add_file_to_knowledge_by_id), and backend/open_webui/routers/knowledge.py (add_files_to_knowledge_by_id_batch). This vulnerability is fixed in 0.9.5.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openwebui | Open Webui | < 0.9.5 |
Related Weaknesses (CWE)
References
- https://github.com/open-webui/open-webui/security/advisories/GHSA-r472-mw7m-967fExploitMitigationVendor Advisory
- https://github.com/open-webui/open-webui/security/advisories/GHSA-r472-mw7m-967fExploitMitigationVendor Advisory
FAQ
What is CVE-2026-45402?
CVE-2026-45402 is a vulnerability with a CVSS score of 8.1 (HIGH). Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, multiple endpoints accept a user-supplied file_id and attach the referenced file to a...
How severe is CVE-2026-45402?
CVE-2026-45402 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-45402?
Check the references section above for vendor advisories and patch information. Affected products include: Openwebui Open Webui.