Apple iPhone users have publicised a simple procedure to bypass the handset's access passcode protection.
The flaw has been publicised on the MacRumors website. A person not authorised to use the phone can hit the device's "emergency call button" on the iPhone's passcode entry screen.
This brings up a dial pad for placing an emergency call, but it also allows the rogue user to press the iPhone's "home" button.
By default, the home button is set to bring up the user's "favourites" list. And it also enables an unauthorised user to access a number of other features on the phone.
From within the favourites list, an unauthorised user can view the contact details of people within the iPhone owner's address book.
They can also access the owner's voice-mail from the list, and click on a contact's e-mail address to open up the mail application or Safari web browser.
They would then have access to all of the user's e-mail messages and stored web bookmarks.
Apple is said to be aware of the issue and working to fix the problem.
A simple workaround is already available though. Users can set the destination of the "home" button to the actual Home screen, which requires the passcode to access features.
This is the latest problem to hit the iPhone. Users have complained about poor battery performance and continuous dropped 3G calls.
Apple has also had to contend with a phishing flaw on the device, and, this week, the Advertising Standards Authority said Apple would have to pull a TV ad because of misleading promises about full web access with the iPhone.