CVE-2026-44552: Openwebui Open Webui

High severity, CVSS 8.7. EPSS: 0.4% chance of exploitation in the next 30 days.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the tool_servers and terminal_servers keys in utils/tools.py do use a prefix. When two or more Open WebUI instances share a Redis database (a supported and documented deployment pattern, e.g., for multi-region deployments, blue-green setups, or cluster topologies), the unprefixed keys collide. An admin on Instance A writing to tool_servers overwrites the value read by Instance B — causing Instance B's users to receive Instance A's tool server configuration. This vulnerability is fixed in 0.9.0.

Affected products

• Openwebui Open Webui: before 0.9.0 (fixed in 0.9.0)

Published 2026-05-15. Last modified 2026-06-17.