A man has claimed he can open his wife's smartphone by using his own face, despite Apple claiming the chances of bypassing the facial recognition feature are one in a million.
Phill Bland told The Sun he discovered the glitch after realising a glance from him was enough to unlock his wife's iPhone X.
"I asked Apple about it and they say 'No it can only recognise one face'," he was quoted as saying.
"It shouldn't happen. It's just pathetic."
The 44-year-old said he and his wife, Paula, had opted to buy the handsets because they hoped the Face ID technology would stop his two kids from using his phone. However, only weeks after purchasing the iPhone X on a £70-a-month contract with phone provider EE, he realised he could unlock his wife's handset.
Bland suggested the reason behind the glitch might be that the phone now thought he owned his wife's phone, which he had unlocked a number of times by using her passcode.
"We both know each other's codes and I do use her phone if it's lying around, so the only thing we can think is it's started to think I'm her," he said.
Apple's Face ID was one of the most widely anticipated features of the iPhone X which came out on 3 November. Using facial authentication - a sensor which creates a 3D map of the user's face - the phone no longer requires fingerprint access, but simply one look from its owner to open.
The system even learns face changes over time, meaning it can recognise someone in glasses or hats, or with facial hair or different makeup.
"Apple engineering teams have even gone and worked with professional mask makers and makeup artists in Hollywood to protect against attempts to beat Face ID," Phil Schiller, Apple's senior vice president of worldwide marketing, said at the iPhone X launch event.
"These are actual masks used by the engineering team to train the neural network to protect against them in Face ID."
However, the introduction of Face ID has been far from the plain sailing Apple had anticipated. Less than two weeks after the iPhone X was released, researchers at Vietnamese security firm Bkav released a report and a video claiming that they have managed to crack the company's facial recognition technology.
Bkav claimed to have bypassed the Face ID technology using a mask that features both 2D and 3D components, including 3D printed plastic, a silicone nose, makeup and paper cutouts. The proof-of-concept has yet to be publicly confirmed by other security researchers.
Last month, a woman from Nanjing, China, claimed she was unable to rely on Apple's facial recognition technology, while one of her colleagues could easily unlock her phone instead.
The woman had to prove the glitch alongside her co-worker in front of Apple staff before she was believed and allowed access to the phone, Shangaiist.com reported. After exchanging it, the same thing happened again – appearing to highlight an issue with the technology itself, not the individual phone.