Multiple cross-site scripting (XSS) vulnerabilities in SilverStripe CMS & Framework 3.1.13 allow remote attackers to inject arbitrary web script or HTML via the (1) admin_username or (2) admin_password parameter to install.php.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.