Integer overflow in the object_custom function in ext/standard/var_unserializer.c in PHP before 5.4.34, 5.5.x before 5.5.18, and 5.6.x before 5.6.2 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via an argument to the unserialize function that triggers calculation of a large length value. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-3669
