CVE-2026-87012 open-webui CVE debrief

Who should care

Defenders responsible for Open WebUI deployments should assess exposure and prioritize verification and remediation. This includes reviewing user permissions, input validation, and monitoring for similar issues. Security teams and vulnerability management teams should also be aware of the potential impact and take necessary actions to prevent disruptions.

Why it matters

CVE-2026-87012 is a medium-severity vulnerability in Open WebUI that could allow authenticated users to disrupt instance-wide alerts. Defenders should prioritize verification and remediation to prevent potential disruptions.

• Authenticated users with calendar permissions could potentially disrupt reminders for all users
• Instance-wide alert pass could be aborted, requiring manual intervention

Technical summary

The Open WebUI calendar feature did not validate the type of the alert_minutes value, allowing an authenticated user with calendar permissions to store a non-numeric value. This caused an exception during the instance-wide alert pass, suppressing reminders for all users. The vulnerability affects Open WebUI versions from 0.9.0 to 0.11.1 and is fixed in version 0.11.1. Defenders should prioritize verifying and upgrading to the fixed version, reviewing user permissions, and ensuring proper input validation for the calendar feature.

Defensive priority

Defenders should prioritize verifying and upgrading to version 0.11.1 or later, and review user permissions and input validation for the calendar feature.

Recommended defensive actions

• Verify and upgrade to Open WebUI version 0.11.1 or later
• Review user permissions and input validation for the calendar feature
• Monitor for similar input validation issues in other features
• Confirm whether affected product deployments 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 entry provide details on the vulnerability, affected versions, and fixed version. GitHub commit and release notes confirm the patch. Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. Affected versions range from 0.9.0 to 0.11.1. The vulnerability allows an authenticated user with calendar permissions to store a non-numeric value for alert_minutes, causing an exception that aborted the instance-wide alert pass and suppressed reminders for all users.

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.