CVE-2026-45399

HIGH

Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 7.1
EPSS 0.0004
EPSS Percentile 13.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-862
Status published
Products (3)
open-webui/open-webui < 0.9.0
openwebui/open_webui < 0.9.0
pypi/open-webui 0 - 0.9.0PyPI
Published May 15, 2026
Tracked Since May 16, 2026