sapi/fpm/fpm/fpm_unix.c in the FastCGI Process Manager (FPM) in PHP before 5.4.28 and 5.5.x before 5.5.12 uses 0666 permissions for the UNIX socket, which allows local users to gain privileges via a crafted FastCGI client.
https://hoffmann-christian.info/files/php-fpm/0001-Fix-bug-67060-use-default-mode-of-660.patch
https://bugzilla.redhat.com/show_bug.cgi?id=1092815
https://bugs.php.net/bug.php?id=67060
https://bugs.launchpad.net/ubuntu/+source/php5/+bug/1307027
http://www.php.net/archive/2014.php#id2014-05-01-1
http://www.php.net/ChangeLog-5.php
http://www.openwall.com/lists/oss-security/2014/04/29/5
http://support.apple.com/kb/HT6443
http://secunia.com/advisories/59329
http://secunia.com/advisories/59061
http://lists.opensuse.org/opensuse-updates/2015-10/msg00012.html