What’s Vulnerable › Vulnerabilities

CVE-2026-45675: Open WebUI: LDAP and OAuth First-User Race Condition Allows Multiple Admin Accounts

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-15 · updated 2026-06-18
• Weakness: CWE-269

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the LDAP and OAuth authentication flows use a TOCTOU (Time-of-Check-Time-of-Use) pattern for first-user admin role assignment. The regular signup handler (signup_handler in auths.py, line 663) was explicitly patched to prevent this race with the comment "Insert with default role first to avoid TOCTOU race", but the LDAP and OAuth code paths were never updated with the same fix. This vulnerability is fixed in 0.9.0.

Affected products

• open-webui: before 0.9.0 — fixed in 0.9.0

How to fix

Upgrade to a fixed version: open-webui 0.9.0. Check the vendor advisory for mitigations.

References

• https://github.com/open-webui/open-webui/commit/96a0b3239b1aadb23fc359bf10849c9ba12fd6ec
• https://github.com/open-webui/open-webui/pull/23626
• https://github.com/open-webui/open-webui/security/advisories/GHSA-h3ww-q6xx-w7x3

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