CVE-2026-21451: Bagisto has HTML Filter Bypass that Enables Stored XSS

A stored Cross-Site Scripting (XSS) vulnerability exists in Bagisto 2.3.8 within the CMS page editor. Although the platform normally attempts to sanitize <script> tags, the filtering can be bypassed by manipulating the raw HTTP POST request before submission. As a result, arbitrary JavaScript can be stored in the CMS content and executed whenever the page is viewed or edited. This exposes administrators to a high-severity risk, including complete account takeover, backend hijacking, and malicious script execution.