CVE-2026-87994: open-webui

Vulnerability summary

CVE-2026-87994 is a medium (CVSS 4.3) vulnerability in open-webui. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 29.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 09-09-2026
   PublishedVulnerability first disclosed.
2. 10-09-2026
   Last modifiedVulnerability information updated.

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.py checked channel write access and channel membership for a supplied message_id but did not verify that the calling user authored the targeted message. A channel member could use the chat completions endpoint to replace another member's message while preserving the victim as the stored author, altering the conversation record without gaining access to other channels. This issue is fixed in version 0.11.1.

• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
• CWE-862Missing AuthorizationThe product does not perform an authorization check when an actor attempts to access a resource or perform an action.