Multiple cross-site scripting (XSS) vulnerabilities in paginas/vista-previa-form.php in the EnvialoSimple: Email Marketing and Newsletters (envialosimple-email-marketing-y-newsletters-gratis) plugin before 1.98 for WordPress allow remote attackers to inject arbitrary web script or HTML via the (1) FormID or (2) AdministratorID parameter.
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.