HAX CMS helps manage microsite universe with PHP or NodeJs backends. A stored cross-site scripting (XSS) vulnerability exists in versions prior to 26.0.0 due to improper sanitization of <iframe> elements. The application allows javascript: URIs in the src attribute, which are executed when a malicious page is viewed. This enables attackers to execute arbitrary JavaScript in the context of the victim’s browser and access sensitive data exposed to client-side scripts. Version 26.0.0 fixes the issue.