The report states that journalists were able to unlock Pixel 4 multiple times with their eyes closed, which may allow someone other than the owner to gain access to the device. Apple's iPhone uses similar technology, but does not work when its eyes are closed.
"The obvious problem seems to be that you can use it when someone is asleep or even dead," said Nasir Memon, a professor and founder of the NYU cybersecurity program at the Tandon School of Engineering.
Google warns on its Face Unlock support page that the feature could be abused: "Your phone can also be unlocked by another person if it's held to your face, even if your eyes are closed." It is recommended to keep the phone in a front pocket or handbag and to completely switch off the face release in "unsafe situations".
The company's new phones are not yet available to the public: the Pixel 4 and 4 XL ships Oct. 24.
If Face Unlock ships without troubleshooting, the line provides an option to temporarily disable the feature. For added security, users can enable "lockdown mode" via "Preferences" to request a PIN, pattern, or password instead.