Why?

The macOS Security Update is required to prevent bypassing administrator authentication.

Impact

Updates must be installed for macOS High Sierra 10.13, 10.13.1, 10.13.2 macOS Sierra 10.12.6 and earlier are not impacted

Action Needed

Check for updates. If not yet updated, install immediately. See Actions below for additional information about: The content of Security Update 2017-001 Finding build number - when installing Security Update 2017-001, the build number of macOS will be 17B1002 or 17B1003 Root user account on a Mac