FormGet Contact Form 5.3 - Stored XSS

Description

The AJAX action ‘request_response’, defined in formget-contact-form/index.php line 278 is available to any logged in user. The parameter ‘value’ is accepted as valid, so long as the string ‘sideBar’ is found at a position other than 0 (i.e. prefix the payload with a space). The ‘page_id[]’ parameter can be provided in order to specify which pages to display the desired HTML/JS on.