GHSA-h3ww-q6xx-w7x3: Open WebUI: LDAP and OAuth First-User Race Condition Allows Multiple Admin Accounts

Summary

Open WebUI's LDAP and OAuth authentication flows determine a new user's role before inserting the user, creating a time-of-check-time-of-use race on fresh instances. Concurrent first-login requests can all observe an empty user table and all receive the admin role, while the signup handler had already been patched against this pattern. The LDAP and OAuth paths were not updated, so any user who times a first login concurrently with the legitimate first admin can gain full admin privileges, including access to user data, system configuration, API keys, and connected LLM backends.

Mitigation

Fixed in PR #23626 (commit 96a0b3239), first released in v0.9.0 (Apr 2026). LDAP and OAuth registration now insert the new user with DEFAULT_USER_ROLE, then check Users.get_num_users() == 1 and promote only the sole user to admin. Users on >= 0.9.0 are not affected.

Affected packages in the Exposure Registry

Matched by package name and ecosystem. Each entry shows whether the package delegates to a language model and how many tracked packages depend on it.

• open-webuiPyPILLM dependency since 2024-05-20

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