The phar_parse_tarfile function in ext/phar/tar.c in PHP before 5.4.41, 5.5.x before 5.5.25, and 5.6.x before 5.6.9 does not verify that the first character of a filename is different from the \0 character, which allows remote attackers to cause a denial of service (integer underflow and memory corruption) via a crafted entry in a tar archive.
https://support.apple.com/kb/HT205031
https://security.gentoo.org/glsa/201606-10
http://www.securitytracker.com/id/1032433
http://www.securityfocus.com/bid/74700
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://www.debian.org/security/2015/dsa-3280
http://rhn.redhat.com/errata/RHSA-2015-1219.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://lists.opensuse.org/opensuse-updates/2015-06/msg00002.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-May/159031.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-May/158915.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-May/158616.html
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html