CVE-2026-45349 Open WebUI: Broken Access Control for Completions API

What is CVE-2026-45349?

CVE-2026-45349 is a high-severity missing authorization vulnerability in Openwebui Open Webui, published on 15 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, a user just needs to use the API endpoint: /api/chat/completions with their own API key (generated in OWUI) and the Chat ID of another user to continue the conversation of the other user. This vulnerability is fixed in 0.9.0.

Weakness: CWE-639

Which versions are affected by CVE-2026-45349?

3 open source packages ship an affected version, including open-webui. It affects 1 product.

Products include Openwebui Open Webui.

How do I fix CVE-2026-45349?

Upgrade open-webui to 0.9.0 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-45349 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45349 exists.

Other vulnerabilities in Openwebui Open Webui

• CVE-2026-44551 Open WebUI: LDAP Empty Password Authentication Bypass Critical 9.1
• CVE-2026-56400 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation Critical 9.0
• CVE-2024-8017 Cross-site Scripting (XSS) in open-webui/open-webui Critical 9.0
• CVE-2026-45672 Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed High 8.8
• CVE-2026-87995 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin High 8.7

All Openwebui Open Webui vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-gfm2-xm6c-37qc, PYSEC-2026-2726.