The Social subsystem in Apple iOS before 7 does not properly restrict access to the cache of Twitter icons, which allows physically proximate attackers to obtain sensitive information about recent Twitter interaction via unspecified vectors.
http://www.securitytracker.com/id/1029054
http://support.apple.com/kb/HT5934
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html