Turn off access to Control Center from the lock screen! It’s not worth the risk. There is another way to bypass the lock screen in iOS7 – if you have a missed call and have access to Control Center from lock screen turned on anyone can have access to whatever app you have running in the foreground. EverythingApplePro has a short video showing the vulnerability http://youtu.be/Hg9Vy7XzGZY
But at least there is an easy fix until Apple comes out with a patch, just turn off access to the Control Center from locked screen for now. Not a huge inconvenience.