That was quick.
Apple just this week released a fix for the highly publicized lock screen bypass that was discovered in mid-February. Unfortunately, it seems another trick that allows similar access to the device has already been discovered.
According to The Next Web, this vulnerability is present in iOS 6.1.3. This version was just released earlier this week and contained a number of bug fixes along with a fix for the lock screen bypass. The method for bypassing the lock screen in that instance was pretty complicated. This time, it's much, much easier.
Before, bypassing the lock screen involved a complicated series of taps, interrupted emergency calls, and attempting to the turn the phone off. This time, all you need is for voice dialing to be enabled and to pull out the SIM card mid-call. This brings up the dialer and from there you can access photos, call history, and more.
Apple hasn't commented on this new hole but we'll keep you posted. For now, you can protect your phone by switching off voice dial in the passcode lock section in the Settings menu.