There is a bug with HomeKit which for the name doorLock and which crashes both iPhone and iPad. It was discovered by security researcher Trevor Spiniolas. A “positive” point exists in this matter: there is very little chance that you are affected.
When HomeKit crashes iPhones due to a bug
When the name of a HomeKit device is changed with a large string (500,000 characters in tests), any iPhone or iPad that has an affected version of iOS installed and loads the name will be disrupted, even after a restart. The device no longer saves commands, as if the touch screen no longer works.
The real problem in this story is that there is a link with the Apple account. Indeed, it is possible to restore your device so that the bug disappears. But logging in with your Apple account will reset the doorLock bug.
The security researcher notified Apple of this bug on August 10, 2021. The manufacturer had initially informed him that a patch would be available before the end of 2022. We have started the new year and the patch is still not here. Apple is now telling the researcher that its update will arrive in early 2022, without further clarification. Trevor Spiniolas, however, finds that Apple takes this problem lightly and takes far too long to correct it, hence the details being released publicly.
A temporary solution before Apple’s patch
He points out that in iOS 15.1, Apple added a limit to the length of the name an app or user can set for a HomeKit accessory. But that’s not enough to put a definitive fix on the general concern. Notably, the bug affects users even if they don’t have HomeKit devices added. This happens if someone accepts an invitation that contains a HomeKit device with a large string as the name. This is true even on the latest version of iOS, namely iOS 15.2.
Upon arrival, your iPhone will crash and restart if you have HomeKit devices enabled in Control Center. If you don’t have one, the Home app is crashing. A temporary solution to avoid the bug is to go to Settings> Control Center and then deactivate “House Controls”.