systemstatsd in the System Stats subsystem in Apple OS X before 10.10.4 does not properly interpret data types encountered in interprocess communication, which allows attackers to execute arbitrary code with systemstatsd privileges via a crafted app, related to a "type confusion" issue.
http://www.securitytracker.com/id/1032760
http://www.securityfocus.com/bid/75493
http://support.apple.com/kb/HT204942
http://lists.apple.com/archives/security-announce/2015/Jun/msg00002.html