Improper Access Control Leads to Server-Side Request Forgery in Mautic

Users with low privileges can perform certain AJAX actions. In this vulnerability instance, improper access to ajax?action=plugin:focus:checkIframeAvailability leads to a Server-Side Request Forgery by analyzing the error messages returned from the back-end. Allowing an attacker to perform a port scan in the back-end. At the time of publication of the CVE no patch is available.