KLA11699
Windows Hello for Business Security update

After a user sets up Windows Hello for Business (WHfB), the WHfB public key is written to the on-premises Active Directory. The WHfB keys are tied to a user and a device that has been added to Azure AD, and if the device is removed, the corresponding WHfB key is considered orphaned. However, these orphaned keys are not deleted even when the device it was created on is no longer present. Any authentication to Azure AD using such an orphaned WHfB key will be rejected. However, some of these orphaned keys could lead to the following security issue in Active Directory 2016 or 2019, in either hybrid or on-premises environments.

Windows

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)

ADV190026