Apple has today released a minor update for iOS and iPadOS, with iOS 15.2.1 and iPadOS 15.2.1. Both are very light in terms of additions or bug fixes, but it does address an important security issue that is present in HomeKit.
iOS 15.2.1 and iPadOS 15.2.1 are available now to download, as usual for free. Your device can be updated by going to Settings > General > Software Update.
Apple has addressed an issue with some third party apps on CarPlay not responding as well as an issue that could cause some Messages sent that contain an iCloud link not to be sent.
The issue with HomeKit has been also addressed, this vulnerability was discovered in 2021 and it could cause a malicious HomeKit name to then result in in a denial of service, which would cause a users iPhone or iPad devices to not work. The only way to get the iPhone to respond again was to do a forced reset of the device.