A security problem with iOS 6.1 could potentially allow anyone to bypass the lock screen on a device running the OS and access the data on the phone.
The issue allows anyone who knows the trick to unlock a phone and access call logs, contacts, favourite contacts, make calls and even access photos on the device by trying to add a photo to a contact.
The issue was uncovered by YouTube user videosdebarraquito and involves quickly making and cancelling an emergency call and holding down the power button.
The iOS 6.1 operating system has suffered a number of bugs including excessive logging issues when connected to an Exchange server. It also had issues with 3G that lead UK network operator Vodafone to advise its customers not to update their handsets until the problem had been rectified.
A subsequent update to iOS 6.1.1 led Vodafone to tell customers to go ahead and update. It's also not the first time that an Apple update has left handsets vulnerable — iOS 4.1 had a very similar issue that let anyone bypass the lock screen.
Apple had not responded to a request for comment at the time of publication.