applications/core/modules/front/system/content.php in Invision Power Services IPS Community Suite (aka Invision Power Board, IPB, or Power Board) before 4.1.13, when used with PHP before 5.4.24 or 5.5.x before 5.5.8, allows remote attackers to execute arbitrary code via the content_class parameter.
https://www.exploit-db.com/exploits/40084/
https://support.apple.com/HT207170
https://invisionpower.com/release-notes/4113-r44/
http://www.securityfocus.com/bid/91732
http://packetstormsecurity.com/files/137804/IPS-Community-Suite-4.1.12.3-PHP-Code-Injection.html
http://lists.apple.com/archives/security-announce/2016/Sep/msg00006.html