ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Versions of sanitize-html prior to 2.17.5 use "allowedSchemesAppliedToAttributes" (default: "['href', 'src', 'cite']") to gate the "naughtyHref()" function that blocks dangerous URI schemes like "javascript:" and "vbscript:". The HTML specification defines 10+ attributes that accept URIs ("action", "formaction", "data", "poster", "background", "ping", "xlink:href", "dynsrc", "lowsrc"), but none of these are included in the default gate list. When a developer allows any of these attributes in their configuration, "javascript:" URIs pass through completely unmodified, enabling XSS. Version 2.17.5 patches the issue.