Apple just released a patch that fixes a recently revealed security vulnerability in High Sierra. This is the bug that let anyone gain admin access to Mac accounts without typing in a password. Apple is making it very easy to update your software and squash the bug. If youre running High Sierra, you should soon see a pop-up that looks like this: “You should do the security update because you do not want this bug on your Mac” Now that news of the vulnerability is out in the wild, hackers will be rushing to exploit it.”]
Source: https://gizmodo.com/how-to-fix-that-very-bad-security-bug-in-macos-1820843370