Open WebUI — Vulnerability (CVE-2026-44558)
Date: 2026-05
Affected: openwebui/open_webui
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2026-44558
CWE: CWE-862
CVSS: 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.


Mitigations:

Architectural layers (MAESTRO):