In the past days a lot of iPhone 4S said that there is a security flaw regarding Siri as it work from lock screen but this is not true as it is a feature from Apple and you can turn off Siri from the lock screen in the iPhone 4S settings menu.Now there is a real security flaw regarding iPad 2 with a smart cover , a video from 9to5mac will show this issue .
As you can see in our video above, a Smart Cover can essentially unlock an iPad 2. The person who unlocks your iPad 2 will not have complete access to your iPad, but will be able to gain entrance to whatever you locked your iPad 2 on. If your iPad 2 went to sleep in Mail, Safari, Messages, Contacts, or Maps, you can imagine the sorts of personal information that can be viewed on your iPad. If you left your iPad 2 on its home screen, the person can view which applications you have on your device, control media from the multitasking bar, but not much else.
How to re-create it:
1) Lock a password protected iPad 2
2) Hold down power button until iPad 2 reaches turn off slider
3) Close Smart Cover
4) Open Smart Cover
5) Click cancel on the bottom of the screen