Apple iOS 12 - An attacker with physical access to a user’s device could partially unlock the person’s content as long as Siri is enabled and Face ID is either disabled or physically covered.(Luckily, it is a complex process and involves more than 30 steps)

Those who fear their device may be vulnerable to this and other attacks can increase their security by disabling Siri from the lock screen by going into Settings/Touch ID & Passcode, scrolling down to the “Allow access when locked” section and ensuring that Siri is disabled.


https://www.scmagazine.com/home/news/apple-ios-12-passcode-bypass-allows-unauthenticated-access-to-iphone-features/