Buffer overflow in International Components for Unicode (ICU) in Apple Mac OS X before 10.6.8 allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via vectors involving uppercase strings.
lists.apple.com/archives/security-announce/2011//Jul/msg00002.html
lists.apple.com/archives/security-announce/2011//Jun/msg00000.html
lists.apple.com/archives/Security-announce/2011//Oct/msg00001.html
support.apple.com/kb/HT4723
support.apple.com/kb/HT4808
support.apple.com/kb/HT4999
exchange.xforce.ibmcloud.com/vulnerabilities/68217