It took less than 24 hours for someone to find a way to break through iOS 7's passcode feature, and wouldn't you know it: the new Control Center is to blame. By going through a rather simple series of swipes and taps, a user can bypass the lock screen on some iOS 7 devices. You start in the Control Center, switch to the Timer, then double-tap the home button which lets you access the multitasking feature, allowing you to browse apps without having to unlock the device.
I say "some" because there's a rather simple tweak you can perform that will prevent someone from using this nasty trick on your own iPhone or iPad: Simply go to Settings -> Control Center and toggle the "Access on Lock Screen" option to "off." Ta-da! You're safe!
Update: Apple is working on a fix.
Update 2: According to multiple reports, accessing the multitasking menu through the Timer glitch only produces blank screenshots, but using the glitch while in the Camera app gets the job done.
Apple iPad Air 2
Apple iPhone 6s