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.
https://support.apple.com/HT205267
https://security.gentoo.org/glsa/201503-03
https://bugs.php.net/bug.php?id=68676
http://www.securityfocus.com/bid/71800
http://www.oracle.com/technetwork/topics/security/bulletinjul2015-2511963.html
http://rhn.redhat.com/errata/RHSA-2015-1218.html
http://openwall.com/lists/oss-security/2014/12/29/6
http://lists.apple.com/archives/security-announce/2015/Sep/msg00008.html
http://git.php.net/?p=php-src.git%3Ba=commit%3Bh=fbf3a6bc1abcc8a5b5226b0ad9464c37f11ddbd6
http://git.php.net/?p=php-src.git%3Ba=commit%3Bh=2bcf69d073190e4f032d883f3416dea1b027a39e
http://git.php.net/?p=php-src.git%3Ba=commit%3Bh=24125f0f26f3787c006e4a51611ba33ee3b841cb