CVE 2015-8876

Zend/zend_exceptions.c in PHP before 5.4.44, 5.5.x before 5.5.28, and 5.6.x before 5.6.12 does not validate certain Exception objects, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) or trigger unintended method execution via crafted serialized data.

See the CVE page on Mitre.org for more details.