Unrestricted file upload vulnerability in class/ApplyDB.php in ClassSystem 2.3 allows remote attackers to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in class/UploadHomepage/.
https://exchange.xforce.ibmcloud.com/vulnerabilities/42651
http://www.vupen.com/english/advisories/2008/1664
http://www.securityfocus.com/archive/1/492583/100/0/threaded