Cross Site Scripting (XSS) vulnerability in GetSimpleCMS <= 3.3.15 in admin/changedata.php via the redirect_url parameter and the headers_sent function.
Cross Site Scripting vulnerability in GetSimpleCMS 3.3.16 in admin/upload.php by adding comments or jpg and other file header information to the content of xla, pages, and gzip files,
GetSimple CMS 3.3.16 allows in parameter 'permalink' on the Settings page persistent Cross Site Scripting which is executed when you create and open a new page