Multiple eval injection vulnerabilities in MyBB 1.2.10 and earlier allow remote attackers to execute arbitrary code via the sortby parameter to (1) forumdisplay.php or (2) a results action in search.php.
https://www.exploit-db.com/exploits/4928
https://www.exploit-db.com/exploits/4927
http://www.securityfocus.com/bid/27322
http://www.securityfocus.com/archive/1/486434/100/0/threaded