Use-after-free vulnerability in the process_nested_data function in ext/standard/var_unserializer.re in PHP before 5.4.37, 5.5.x before 5.5.21, and 5.6.x before 5.6.5 allows remote attackers to execute arbitrary code via a crafted unserialize call that leverages improper handling of duplicate numerical keys within the serialized properties of an object. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-8142.<a href=http://cwe.mitre.org/data/definitions/416.html>CWE-416: Use After Free</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-0231