CVE-2026-87998 open-webui CVE debrief

Who should care

Defenders responsible for Open WebUI instances, particularly those with write access to knowledge base configurations, should assess exposure and apply the patch to prevent unauthorized deletion of knowledge base configurations.

Why it matters

CVE-2026-87998 is a high-severity vulnerability in Open WebUI that allows unauthorized deletion of knowledge base configurations, potentially impacting multiple knowledge bases. Defenders should prioritize verifying exposure and applying the patch.

• Potential deletion of shared instance configurations by non-administrators.
• Possible unavailability of knowledge bases using the same connection.
• Need for verification of exposure and application of the patch.

Technical summary

The vulnerability exists in the DELETE /api/v1/knowledge/{id}/delete endpoint in Open WebUI, allowing a non-administrator with write access to delete knowledge base configurations without a separate administrator check or a check for dependent knowledge bases. This issue is fixed in version 0.11.1. The vulnerability has a CVSS score of 7.1 and is considered high severity. Defenders should prioritize verifying exposure and applying the patch to prevent unauthorized deletion of knowledge base configurations. The technical details are based on publicly available information and may not be comprehensive.

Defensive priority

Defenders should prioritize verifying exposure and applying the patch, as the vulnerability allows for unauthorized deletion of knowledge base configurations.

Recommended defensive actions

• Verify exposure by checking if the Open WebUI instance is running a vulnerable version (between 0.10.0 and 0.11.1).
• Apply the patch by upgrading to version 0.11.1 or later.
• Review and restrict write access to knowledge base configurations to prevent unauthorized deletion.
• Monitor for suspicious activity related to knowledge base deletions.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability is described in the CVE record and NVD vulnerability detail page. The issue is fixed in version 0.11.1, and patches are available in the referenced GitHub commits and release notes. Defenders should verify exposure by checking if the Open WebUI instance is running a vulnerable version (between 0.10.0 and 0.11.1) and apply the patch by upgrading to version 0.11.1 or later. The evidence is limited to publicly available information and may not be comprehensive.

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.