When Google LLC came up with its face unlock system for its the Pixel 4 and 4 XL phones, it said the technology should be used across all Android devices. Maybe not so much anymore.

In an article published by the BBC today, it was revealed that the system has perhaps a fatal flaw: The phone can be unlocked even if the person’s eyes are closed. That’s different from Apple Inc.’s “Face ID” system, which does require one’s eyes to be open.

“If someone can unlock your phone while you’re asleep, it’s a big security problem,” a cybersecurity expert told the BBC. “Someone unauthorized — a child or partner? — could unlock the phone without your permission by putting it in front of your face while you’re asleep. I wouldn’t trust it to secure the private conversations and data on my phone.”

Compounding the problem, the Pixel 4 phones don’t include any fingerprint censors. The only biometric authentication system for these devices will be the facial recognition technology.

Google’s support page explains that indeed the phone can be unlocked when held up to a face even if the owner of that face is asleep or perhaps unconscious, although Google adds that there is a “Lockdown” mode for people who might be concerned about that.

The problem is that many people won’t apply this setting every time they take a nap, which might leave them vulnerable. In the case of Apple’s face unlock system, the company said that “requiring attention makes Face ID more secure.” There are also concerns that authorities might easily to be able to get into a person’s phone if this isn’t fixed.

“We will continue to improve Face Unlock over time,” Google said in a statement, and it seems the company is trying out different features. In one of the leaked demos of the Pixel 4, there was actually an option that read, “Require eyes to be open.” It’s just that his option doesn’t seem to be available on the first phones that will be shipped next week.

Photo: bradleypjohnson/Flickr