There was already a bug regarding lockscreen in iOS 7 and another bug has also appeared, its something like allowing to make a call with a locked screen.
It was first reported by Karam Daoud, a 27-year old Palestinian living in the West Bank city of Ramallah on Friday, through a video, in which he is trying to show how he is able to make a call to any number from a locked iPhone running iOS 7 by exploiting a vulnerability in its emergency calling function. Through this a thief could easily take advantage of it because there is a possibility of making international calls and calls to premium numbers.
If the iPhone screen is locked one can press “Emergency”, which brings the dialing screen so, he or she can dial any number and rapidly tap the call button until the phone reverts to an empty screen with an Apple logo, says Daoud. He also elaborated that he had tested this trick on two iPhone 5 and it worked in both cases although more than a minute of tapping the second time.
Daoud already explained the flaw to Apple’s security team. After examining these bugs, an Apple contact wrote to him again to thank him for the information and assured that it will be fixed in the coming software updates.