CVE-2026-45665: Open WebUI has Stored XSS in Banner Component via Improper Sanitization Order

A Stored Cross-Site Scripting (XSS) vulnerability exists in the Banner component due to an improper sanitization order (specifically, DOMPurify is executed before the marked library).

This vulnerability allows a compromised or malicious administrator to plant a malicious payload in the global banner. Crucially, this vector enables Privilege Escalation, as the malicious banner is rendered for all users, including the Super Admin (Primary Admin).

Consequently, the payload successfully bypasses the existing security mechanism. An attacker can leverage this to steal the Super Admin’s session token