A leak in the PDF reader for the iPhone makes it possible to hack the handset. This lets you use alternative app stores such as Cydia app, where unapproved apps can be found.
The leak is now used by the famous JailbreakMe website, where an easy iPhone or iPad jailbreak can be dome. Many advanced users of the Apple smartphone like a jailbreak, because of the extra features it offers. Apple is in constant conflict with the jailbreakers, and tries to make avery jailbreak impossible with a patch.
The hole in the PDF reader is not only a joy for people who want form from their their iPhone then Apple allows. The vulnerability can also be used by malicious software. Everything that is needed is, is a PDF file. You can then gain root access to the smartphone and tablet from Apple, and which makes stealing data a piece of cake.
Source: Pcworld.com