Apple’s iOS devices have seen plenty of passcode-related security flaws in the past. iPhoneIslam (via Macgasm) points out a new security flaw that could allow anyone with access to your phone, a paperclip, and a fair bit of patience to view your call history, or even see your entire address book. I recommend pushing forward to about 2:40 in the below video to save yourself some time.
I’m not sure how likely this scenario is – for someone to gain access to your iPhone for several minutes – long enough to eject your SIM card multiple times without being noticed. Still, if your iPhone is swiped, this could be a significant point of concern.
As you can see, the trick relies on trying to make a call using the missed call notification, then ejecting and reinserting the SIM card. The hack only works if your device currently doesn’t have a signal (hence the SIM card trickery).
The bug is definitely a problem that needs to be patched, to be sure, but its unclear how much any individual iPhone user should really worry about this in the meantime.