PHP before 5.4.40, 5.5.x before 5.5.24, and 5.6.x before 5.6.8 does not ensure that pathnames lack %00 sequences, which might allow remote attackers to read arbitrary files via crafted input to an application that calls the stream_resolve_include_path function in ext/standard/streamsfuncs.c, as demonstrated by a filename\0.extension attack that bypasses an intended configuration in which client users may read files with only one specific extension.
http://www.securitytracker.com/id/1032709
http://www.securityfocus.com/bid/75250
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://rhn.redhat.com/errata/RHSA-2015-1218.html
http://rhn.redhat.com/errata/RHSA-2015-1187.html
http://rhn.redhat.com/errata/RHSA-2015-1186.html
http://rhn.redhat.com/errata/RHSA-2015-1135.html
http://php.net/ChangeLog-5.php
http://git.php.net/?p=php-src.git%3Ba=commit%3Bh=4435b9142ff9813845d5c97ab29a5d637bedb257