inc/init.php in Archive Mode (Light) in MyBB (aka MyBulletinBoard) 1.1.4 calls the extract function with EXTR_OVERWRITE on HTTP POST and GET variables, which allows remote attackers to overwrite arbitrary variables, as demonstrated via an SQL injection using the _SERVER[HTTP_CLIENT_IP] parameter in archive/index.php.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27445
http://www.mybboard.com/archive.php?nid=15