CVE-2026-87997 open-webui CVE debrief

Who should care

Defenders and administrators of Open WebUI instances should assess exposure and apply the patch to prevent potential unauthorized chat injections. They should review and restrict folder access and write permissions for authenticated users and monitor for suspicious chat injection attempts.

Why it matters

CVE-2026-87997 is a vulnerability in Open WebUI that allows authenticated users to inject chats into folders without write access, potentially affecting folder readers. Defenders should prioritize verifying and applying the patch to prevent potential unauthorized chat injections.

• Potential unauthorized chat injections into folders without proper write access checks
• Possible exposure of folder readers to attacker-controlled content

Technical summary

The vulnerability exists in Open WebUI versions from 0.10.0 until 0.11.1, where the POST /api/chat/completions and POST /api/v1/chat/completions endpoints copied a client-supplied folder_id into a new chat without applying the folder write-access check used by the dedicated chat routes. This allows an authenticated user who knew a shared folder identifier to inject an attacker-controlled chat into a folder where the user had read-only or no write access, causing the entry to appear to authorized folder readers. The issue is fixed in version 0.11.1.

Defensive priority

Defenders should prioritize verifying and applying the patch to prevent potential unauthorized chat injections.

Recommended defensive actions

• Verify and apply the patch by updating to version 0.11.1 or later
• Review and restrict folder access and write permissions for authenticated users
• Monitor for suspicious chat injection attempts
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability allows an authenticated user to inject a chat into a folder without write access, potentially affecting folder readers. The issue arises from the POST /api/chat/completions and POST /api/v1/chat/completions endpoints copying a client-supplied folder_id into a new chat without applying the folder write-access check used by dedicated chat routes. Defenders should verify and apply the patch by updating to version 0.11.1 or later and review and restrict folder access and write permissions for authenticated 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.