SQL injection vulnerability in the init function in class_session.php in MyBB (aka MyBulletinBoard) 1.1.5 allows remote attackers to execute arbitrary SQL commands via the CLIENT-IP HTTP header ($_SERVER['HTTP_CLIENT_IP'] variable), as utilized by index.php.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27752
http://www.vupen.com/english/advisories/2006/2811
http://www.securityfocus.com/archive/1/440163/100/0/threaded
http://www.mybboard.com/archive.php?nid=16