Soon after iOS 7 came out, a pair of holes in the lockscreen were outed and then quickly fixed in iOS 7.0.2.
It turns out that Apple didn't fix future problems of this sort proactively, because the just-announced iOS 7.0.3 closes three more locked-phone holes.
The three bugs this time deal with similar problems to those patched in 7.0.2:
• Another flaw in the emergency call feature, where hitting the call button at a carefully-planned moment lets you call any number, not just 911 or your local equivalent.
• A passcode lockout bypass, so that crackers can continue trying passcodes even after the phone decides they've had too many goes and locks them out.
• Access to the Contacts pane even when the phone is locked.
Interestingly, the bug fix for the emergency call problem is described as follows:
[Apple-related: Mac OS X 10.9 Mavericks is out. It's free. And I'm not installing it]