libarchive in Apple OS X before 10.11.1 allows attackers to write to arbitrary files via a crafted app that conducts an unspecified symlink attack.
https://support.apple.com/HT205375
https://euvd.enisa.europa.eu/vulnerability/EUVD-2015-6916
http://lists.apple.com/archives/security-announce/2015/Oct/msg00005.html