CVE-2026-44559: Openwebui Open Webui

Medium severity, CVSS 4.3. EPSS: 0.3% 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 GET /api/v1/channels/{id}/members endpoint only checks membership for group and dm channel types (lines 467-469). For standard channels — including private ones — there is no channel_has_access check before returning the member list. Any authenticated user who knows a private channel's UUID can enumerate all users with access to that channel. 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.