Bugs in WatchOS 4, 4.1 and 4.2, and in iOS 11.2 apparently made it possible for someone to access your HomeKit-enabled products and control them remotely.
HomeKit is Apple's smart home platform. If you buy a HomeKit-enabled device you can use the related Home app for iPhone and iPad to manage and control your connected products. You can also enlist Siri to lock doors, adjust lights and more via voice commands.
Apple issued a patch on Dec. 7, Khaos Tian claims, but it's still working on a more permanent solution. In the meantime, you won't be able to add new people to your HomeKit home or allow existing users to access HomeKit devices remotely.
Apple did not immediately respond to CNET's request for comment.