The make_http_soap_request function in ext/soap/php_http.c in PHP before 5.4.44, 5.5.x before 5.5.28, and 5.6.x before 5.6.12 does not properly retrieve keys, which allows remote attackers to cause a denial of service (NULL pointer dereference, type confusion, and application crash) or possibly execute arbitrary code via crafted serialized data representing a numerically indexed _cookies array, related to the SoapClient::__call method in ext/soap/soap.c.
https://bugs.php.net/bug.php?id=70081
http://www.ubuntu.com/usn/USN-2952-2
http://www.ubuntu.com/usn/USN-2952-1
http://www.securityfocus.com/bid/84426
http://rhn.redhat.com/errata/RHSA-2016-2750.html
http://php.net/ChangeLog-5.php
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00058.html
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00057.html
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00056.html
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00052.html