Vulnerability Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI supports model composition via base_model_id: a user-defined model (e.g., "Cheap Assistant") can reference an existing base model (e.g., "gpt-4-turbo-restricted") that provides the actual inference capability. When a user queries the composed model, the access control pipeline verifies the user has access to the composed model but never re-verifies access to the chained base model. Additionally, the model creation and import endpoints accept arbitrary base_model_id values without checking that the caller has access to that base model. Combined, this allows any user with the default model creation permission to create a model that chains to a restricted base model — and then invoke it, causing the server to dispatch the request to the restricted base model using the admin-configured API key. This vulnerability is fixed in 0.9.0.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openwebui | Open Webui | < 0.9.0 |
Related Weaknesses (CWE)
References
- https://github.com/open-webui/open-webui/security/advisories/GHSA-9vvh-qmjx-p4q8ExploitVendor Advisory
- https://github.com/open-webui/open-webui/security/advisories/GHSA-9vvh-qmjx-p4q8ExploitVendor Advisory
FAQ
What is CVE-2026-44555?
CVE-2026-44555 is a vulnerability with a CVSS score of 7.6 (HIGH). Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI supports model composition via base_model_id: a user-defined model (e.g., ...
How severe is CVE-2026-44555?
CVE-2026-44555 has been rated HIGH with a CVSS base score of 7.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44555?
Check the references section above for vendor advisories and patch information. Affected products include: Openwebui Open Webui.