u5CMS is a little, handy Content Management System for medium-sized websites, conference / congress / submission administration, review processes, personalized serial mails, PayPal payments and online surveys based on PHP and MySQL and Apache.
Input passed to the 'f' parameter in 'deletefile.php' is not properly sanitised before being used to delete files. This can be exploited to delete files with the permissions of the web server using their absolute path or via directory traversal sequences passed within the affected GET parameter.