There’s a security flaw in iOS for the iPad 2 that lets anyone with a Smart Cover access your passcode-locked device.
9to5 Mac discovered the flaw, and has a video demo (embedded below) of how it works. The flaw allows anyone to access the screen you left open before your iPad fell asleep.
For example, if you leave your iMessage app open and your iPad falls asleep, anyone can use this hack to access your messages.
Same goes for Safari, contacts, etc.
Here’s how it works: