Apple has promised to fix a flaw that allows anyone toon a device running iOS 6.1.
The company has confirmed the issue in a statement sent to ZDNet on Friday, and promised to fix it, although it did not say when.
"Apple takes user security very seriously. We are aware of this issue, and will deliver a fix in a future software update," an Apple spokesman said.
The vulnerability allows anyone that knows the method to access contacts, call logs, messages and pictures (via trying to add a contact picture) on a device without knowing the pin code to unlock it.
iOS 6.1 also brought a number of other issues, such as excessive polling of Exchange servers and 3G connectivity issues, which lead UK operator Vodafone to advise its customers not to update their handsets.
A subsequent patch in iOS 6.1.1; however, this was before the lock screen problem came to light.
This isn't the first time that an iOS update introduced this issue to devices: iOS 4.1 brought similar problems to the iPhone.