WHMCompleteSolution 'cart.php' Local File Disclosure Vulnerability

Summary
WHMCompleteSolution is prone to a local file-disclosure vulnerability because it fails to adequately validate user-supplied input. Exploiting this vulnerability would allow an attacker to obtain potentially sensitive information from local files on computers running the vulnerable application. This may aid in further attacks. Versions prior to WHMCompleteSolution 4.5 are vulnerable.
Solution
The vendor has released updates. Please see the references for details.
References