Vulnerability Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, any authenticated user can overwrite any file's content by ID through the `POST /api/v1/retrieval/process/files/batch` endpoint. The endpoint performs no ownership check, so a regular user with read access to a shared knowledge base can obtain file UUIDs via `GET /api/v1/knowledge/{id}/files` and then overwrite those files, escalating from read to write. The overwritten content is served to the LLM via RAG, meaning the attacker controls what the model tells other users. Version 0.8.6 patches the issue.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openwebui | Open Webui | < 0.8.6 |
Related Weaknesses (CWE)
References
- https://github.com/open-webui/open-webui/security/advisories/GHSA-jjp7-g2jw-wh3jExploitVendor Advisory
FAQ
What is CVE-2026-28788?
CVE-2026-28788 is a vulnerability with a CVSS score of 7.1 (HIGH). Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, any authenticated user can overwrite any file's content by ID through the `PO...
How severe is CVE-2026-28788?
CVE-2026-28788 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-28788?
Check the references section above for vendor advisories and patch information. Affected products include: Openwebui Open Webui.