FreeType in CoreGraphics in Apple iOS before 5.0.1 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted font in a document.
http://support.apple.com/kb/HT5052
http://secunia.com/advisories/48951
http://secunia.com/advisories/46921
http://lists.opensuse.org/opensuse-security-announce/2011-12/msg00008.html
http://lists.apple.com/archives/Security-announce/2011/Nov/msg00001.html