CFNetwork in Apple iOS before 5.1 does not properly construct request headers during parsing of URLs, which allows remote attackers to obtain sensitive information via a malformed URL, a different vulnerability than CVE-2011-3447.
http://www.securitytracker.com/id?1026774
http://secunia.com/advisories/48288
http://lists.apple.com/archives/security-announce/2012/Mar/msg00001.html