Multiple use-after-free vulnerabilities in SPL in PHP before 5.4.44, 5.5.x before 5.5.28, and 5.6.x before 5.6.12 allow remote attackers to execute arbitrary code via vectors involving (1) ArrayObject, (2) SplObjectStorage, and (3) SplDoublyLinkedList, which are mishandled during unserialization.
https://security.gentoo.org/glsa/201606-10
https://bugs.php.net/bug.php?id=70169
https://bugs.php.net/bug.php?id=70168
https://bugs.php.net/bug.php?id=70166
https://bugs.php.net/bug.php?id=70155
http://www.securityfocus.com/bid/76737
http://www.php.net/ChangeLog-5.php