Directory traversal vulnerability in htdocs/install/index.php in XOOPS 2.0.18 allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the lang parameter.
https://www.exploit-db.com/exploits/5057
http://xoops.svn.sourceforge.net/viewvc/xoops?view=rev&revision=1283
http://www.securityfocus.com/bid/27622
http://www.securityfocus.com/archive/1/487484/100/0/threaded