Apple claims the facial recognition system on the new iPhone X is impervious to being fooled by photos, impersonators and masks, but a team of hackers claim to have beaten the technology after just a week.
Cyber security firm Bkav says a 3D-printed mask costing just $150 (£115) to make has fooled the Face ID software, which is used to unlock the iPhone X, authorise payments and log in to apps.
The researchers said it proved that Face ID is "not an effective security measure", although making the mask did require a detailed facial scan, and would be difficult for normal users to replicate.
However, the researchers' demonstration has not been independently verified, and the video does not go through the entire set-up process, so there are likely to be doubts about the supposed flaw.
When the iPhone X was unveiled in September, Apple touted the security benefits of Face ID, saying there is a one in a million chance of another person being able to unlock it, and that it had stress-tested the technology using silicone masks made by Hollywood studios.
Bkav constructed the mask using a combination of 3D printing, a silicone nose and printed images of the eyes. A video released by the company appears to show Face ID being fooled when a cloth covering the mask is removed, although it does not show Face ID being set up, so it cannot be confirmed that the technique works.