CVE-2026-44556

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the /responses endpoint in the OpenAI router accepts any authenticated user and forwards requests directly to upstream LLM providers without enforcing per-model access control. While the primary chat completion endpoint (generate_chat_completion) checks model ownership, group membership, and AccessGrants before allowing a request, the /responses proxy only validates that the user has a valid session via get_verified_user. This allows any authenticated user to interact with any model configured on the instance by sending a POST request to /api/openai/responses with an arbitrary model ID. This vulnerability is fixed in 0.9.0.

Score

CVSS 3.1 7.1 High

Status

Analyzed - security-advisories@github.com

Published

2026-05-15

Last modified

2026-05-15

Weaknesses

CWE-284, CWE-862

Affected products

• Open-webui (Open-webui)
• Open Webui (Openwebui)

References

• https://github.com/open-webui/open-webui/security/advisories/GHSA-hp5m-24vp-vq2q