CVE-2026-45399

High

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users' active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments. This vulnerability is fixed in 0.9.0.

SeverityHigh
CVSS7.1
Exploit probability—
ProductOpenwebui Open Webui
PublishedMay 15, 2026
First seenMay 15, 2026

How to fix

Update
  • openwebui open_webui0.9.0 or later
  • open-webui0.9.0 or later

Affected products

ProductAffected versionsFixed in
openwebui open_webuiv < 0.9.00.9.0
open-webuiPyPIv < 0.9.00.9.0

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CVE-2026-45399 · Openwebui Open Webui · Dark Radar