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

May 14, 2026 (updated May 15, 2026)

Any user X can continue the conversation of any other user Y, as long as the Chat ID of Y is known. User X does not even need to be an admin to do so.

References

github.com/advisories/GHSA-gfm2-xm6c-37qc
github.com/open-webui/open-webui/commit/cf4218e688def6f11d195aeda6665ae5b5376b67
github.com/open-webui/open-webui/releases/tag/v0.9.0
github.com/open-webui/open-webui/security/advisories/GHSA-gfm2-xm6c-37qc
nvd.nist.gov/vuln/detail/CVE-2026-45349

Code Behaviors & Features

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