Double free vulnerability in the zend_ts_hash_graceful_destroy function in zend_ts_hash.c in the Zend Engine in PHP through 5.5.20 and 5.6.x through 5.6.4 allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors.<a href=http://cwe.mitre.org/data/definitions/415.html>CWE-415: Double Free</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-9425