A flaw in iOS 5 could allow an attacker to bypass a stolen phone's passcode and access information such as contacts lists and stored text messages, according to security company Kaspersky.
The flaw lies in a phone's missed call notification, according to a video by iPhone application company iPhone Islam, and would require an attacker to have both physical access to the phone, and know the phone's number.
An attacker can call the phone and quickly remove the SIM card to unlock the device while it searches for a signal, Kaspersky said in a blog post on Wednesday.
iOS 5 has suffered from other flaws that give inappropriate access to data. In October 2011 security company Sophos said that iOS 5 allows access to encrypted messages without an attacker knowing passcodes.