CVE-2026-81911 Concrete CMS versions 9.0.0 to 9.5.2 is vulnerable to Stored XSS in Board Custom Slot save_template via Unescaped Summary Description

Concrete CMS versions 9.0.0 to 9.5.2 is vulnerable to Stored XSS in Board Custom Slot dialog. The customslot savetemplate endpoint authorizes the request only against the target board instance canEditBoardContents and then persists the client-supplied selectedTemplateOptioncollection verbatim,...