Fingerprint scanners are generally more secure than camera-based face unlock solutions, but not all fingerprint unlock solutions are created equally. It seems like Samsung is finding this out the hard way with its Galaxy S10.
News of the Galaxy S10 flaw came via The Sun after a British user told the tabloid that she applied a third-party screen protector to the device. Her husband’s fingerprint was then able to unlock the phone, even though it wasn’t registered on the flagship.
Samsung’s customer support app reportedly noted that the patterns of some third-party screen protectors can be recognized by the Galaxy S10’s ultrasonic fingerprint scanner. The technical details behind the flaw aren’t clear, but it’s definitely a troubling case.
The Galaxy S10 series also serves up camera-based face unlock, but this is less secure than fingerprint authentication anyway. So your best bet is to use a PIN code or to simply not use third-party screen protectors in conjunction with the fingerprint scanner.