Apple closes the Jailbreak.me hole - Update
With an iOS update, Apple has addressed the security hole through which a web site could perform a jailbreak. Apple undercut the previous time taken to release a jailbreak update by just one day. Apart from the security update, iOS 4.3.4 does not seem to contain any changes. Given the risk that iOS devices could be compromised by drive-by downloads, Apple also has a patched iOS 4.2.9 for the CDMA iPhone 4.
There are presently no known web sites trying to exploit the vulnerability in the PDF viewer – which can be triggered without user intervention – but updating is recommended to ensure preventative protection is in place. However, installing the update will prevent jailbreaks from working and will undo the jailbreak on a currently jailbroken phone; for those who prefer their devices jailbroken, it is recommended that they install "PDF Patcher 2" via Cydia and wait for the next jailbreak for the latest iOS versions.
Update - There is though no update for iPhone 3G owners – the last version of iOS for the iPhone 3G was 4.2.1. iPhone 3G users who want to be protected from exploitation of the hole, should jailbreak the device by, for example, using the jailbreak.me site and then install "PDF Patcher 2" with the Cydia installer.