A new bug in iOS 5.0.1 has just been discovered. This bug will allow anyone to initiate FaceTime calls on your iPhone 4S or iPhone 4. Having the highest security settings in place have no effect on this bug.
The iOS 5.0.1 firmware bug we're talking about here has been discovered by Ade Barkah, a technology blogger. He confirms that the bug is present on both the iPhone 4 5.0.1 firmware and iPhone 4S exclusive iOS 5.0.1 firmware. You can implement the highest security settings allowed by iOS, that still won't stop this bug. The only way to fix this would be in form of a software update from Apple itself.
We’re able to trick Voice Control to enumerate through the private address book and make live FaceTime video calls on a locked iPhone 4, even with Voice Dial specifically disabled in the settings. While the iPhone attempts to connect the FaceTime call, it will show the contact’s profile picture if any. So a stranger using your iPhone could possibly see pictures of your contacts even if they do not have FaceTime enabled.
So even if you have passcode lock enabled and Voice Control disabled on your iPhone, this bug will still initiate FaceTime calls and display contacts. By default, Voice Control for iPod is always enabled so that it can be used to play/pause/skip tracks. Disabling Voice Control in Settings.app has no effect on Voice Control for iPod. This works on iPhone 4S as well if Siri is turned off.
We know that the bug can initiate FaceTime calls, it also has the ability to dial voice calls however they do not connect. On the other hand, FaceTime calls connect flawlessly and one can chat with the other party without having to enter the passcode at all. Intricate details about this bug can be read on Ade's blog.
The next firmware update lined for release is iOS 5.1, which is presumably coming out next month. Till then, hold on to that iPhone.