open-webui Open WebUI up to 0.8.x auths.py signup_handler privileges management

Summaryinfo

A vulnerability, which was classified as critical, has been found in open-webui Open WebUI up to 0.8.x. This impacts the function signup_handler of the file auths.py. Performing a manipulation results in privileges management. This vulnerability is reported as CVE-2026-45675. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in open-webui Open WebUI up to 0.8.x. This affects the function signup_handler of the file auths.py. The manipulation with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-45675 since 05/12/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 0.9.0 eliminates this vulnerability. Applying the patch 96a0b3239b1aadb23fc359bf10849c9ba12fd6ec is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• open-webui

Name

• Open WebUI

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

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