https://arstechnica.com/gadgets/2019/10/google-says-a-fix-for-pixel-4-face-unlock-is-months-away/

When the Pixel 4 ships this week, it will be releasing to consumers with a face-unlock security issue that will apparently stick around for some time. Unlike the iPhone's FaceID (and Google's earlier face-unlock system on Android 4.1), the Pixel 4's face unlock doesn't look for the user's eyes, so the phone could be pointed at a sleeping or unconscious owner and unlocked without their consent. This weekend, Google said in a statement that a fix "will be delivered in a software update in the coming months."