CoreText in Apple Mac OS X 10.7.x before 10.7.5 allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds write or read) via a crafted text glyph.
https://exchange.xforce.ibmcloud.com/vulnerabilities/78748
http://support.apple.com/kb/HT5501
http://lists.apple.com/archives/security-announce/2012/Sep/msg00004.html