Facebook owner Meta is warning that up to 1 million Facebook users could have had their logons to the social network stolen by hackers.
The social network says it discovered 400 malicious apps on Apple and Google's app stores that were promoted as photo editors, business or lifestyle software - but actually designed to lure Facebook users into revealing their passwords.
See a full list of the apps here.
Meta says people who think they are affected should:
1. Delete the app in question immediately.