Unisite CMS version 5.0 contains a stored Cross-Site Scripting (XSS) vulnerability in the "Report" functionality. A malicious script submitted by an attacker is rendered in the admin panel when viewed by an administrator. This allows attackers to hijack the admin session and, by leveraging the template editor, upload and execute a PHP web shell on the server, leading to full remote code execution.
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.