CVE-2026-88005 open-webui CVE debrief

Who should care

Defenders responsible for Open WebUI instances, particularly those using OAuth for authentication, should assess exposure and verify the patch to prevent unauthorized sessions. This includes operators managing Open WebUI deployments, platform administrators, vulnerability management teams, and security teams responsible for monitoring and incident response.

Why it matters

CVE-2026-88005 allows unauthorized sessions through Open WebUI's OAuth token exchange endpoint. Defenders should prioritize verifying and applying the patch, reviewing email domain allowlists, and monitoring for suspicious activity.

• Defenders need to verify and apply the patch to prevent unauthorized sessions.
• Email domain allowlists for OAuth login callbacks require review and updates.
• Monitoring for suspicious activity on Open WebUI instances is necessary.

Technical summary

The OAuth token exchange endpoint in Open WebUI issues a session for a provider access token without applying the email domain allowlist that the normal OAuth login callback enforces. This allows an account whose email domain the login callback would refuse to obtain a working session through this endpoint. The issue arises in versions from 0.8.0 until 0.9.0 of Open WebUI. Defenders should focus on verifying and applying the patch to prevent unauthorized sessions, reviewing email domain allowlists, and monitoring for suspicious activity.

Defensive priority

Defenders should prioritize verifying and applying the patch to prevent unauthorized sessions.

Recommended defensive actions

• Verify and apply the patch to prevent unauthorized sessions
• Review and update email domain allowlists for OAuth login callbacks
• Monitor for suspicious activity on Open WebUI instances
• Confirm whether affected Open WebUI instances exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD vulnerability detail page provide information on the vulnerability, its impact, and the fix. However, the corpus does not establish versions, exploitation, impact, or remediation beyond the provided information, requiring verification from the supplied official sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.