Larry Wall's patch; patch in FreeBSD 10.2-RC1 before 10.2-RC1-p1, 10.2 before 10.2-BETA2-p2, and 10.1 before 10.1-RELEASE-p16; Bitrig; GNU patch before 2.2.5; and possibly other patch variants allow remote attackers to execute arbitrary shell commands via a crafted patch file.
https://www.freebsd.org/security/advisories/FreeBSD-SA-15:14.bsdpatch.asc
http://www.securitytracker.com/id/1033110
http://www.securityfocus.com/bid/76116
http://www.openwall.com/lists/oss-security/2015/08/02/6
http://www.openwall.com/lists/oss-security/2015/08/02/1