Apple says it is to change the default settings of its iPhone to stop hackers and others unlocking devices without proper legal authorisation.
The patch prevents an iPhone’s USB port from being used for anything but charging an hour after the device has been locked, blocking access to data.
The move will also make it more difficult for police to unlock handsets without authorization.
The loophole also applies to countries outside the US, including the UK.
“We have the greatest respect for law enforcement, and we don’t design our security improvements to frustrate their efforts to do their jobs.”
The changes to the default settings of the iPhone are intended to stop unauthorized access to the phones via the USB port.