Another security flaw found on iPhone OS (affecting iPhone 3G / 3GS / 4 – iPod touch 2G / 3G and iPad), this time hackers have found exploit on Mobile Safari which is called as PDF Exploit(click here for details). And If you are looking for a immediate fix then you need to make sure that your jailbrokeniPhone/iTouch or you can also update the new upcoming firmware fix from apple (but updating from apple can lock your device for[n]ever). If you are already jailbroken then you need to just install PDF Loading Warner from cydia which is available on BigBoss repo for free. This tweak will warn you if Safari is going to display any PDF without your notice and you can Cancel it if you are unsure about the PDF that you are loading. If you are not jailbroken then you need to first jailbreak your device (You can do it by opening Jailbreakme.com on Mobile Safari, which uses this exploit for jailbreaking iDevices).