A zero day exploit has been released for Apple iPhones and iPads running the most current version of the iOS operating system (version 4.3.3). Exploit code has been identified in the form of malicious PDF files that have been placed on various websites. Apple has indicated a patch will be released but no estimate has been provided when it will be available.
Please see the following URLs for additional details
Update July 15
Apple has released iOS version 4.3.4 to address the vulnerability recently identified in the previous operating system version deployed on iPhone, iPad and iTouch devices. Details are available from the following URL – http://support.apple.com/kb/HT4802
You can download these updates by plugging in your respective iOS device and checking for updates in iTunes