RunCMS before 1.6.1 uses a predictable session id, which makes it easier for remote attackers to hijack sessions via a modified id.
https://www.exploit-db.com/exploits/4790
http://www.securityfocus.com/bid/27019
http://www.securityfocus.com/archive/1/485512/100/0/threaded
http://www.runcms.org/modules/mydownloads/singlefile.php?lid=131