The Speech UI in Apple OS X before 10.10.5, when speech alerts are enabled, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted Unicode string.
https://support.apple.com/kb/HT205031
http://www.securitytracker.com/id/1033276
http://www.securityfocus.com/bid/76340
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html