Auth bypass in Open-Webui
CVE-2026-45399
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (30.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Open-Webui — versions < 0.9.0
- Openwebui Open Webui
Weakness classification (CWE)
References
- github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22 (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-45399?
- CVE-2026-45399 is a high-severity vulnerability in Open-Webui, classified under Missing Authorization. CVSS score: 7.1/10. Published 2026-05-15.
- How severe is CVE-2026-45399?
- High severity. CVSS v3 base score is 7.1 out of 10.