An issue was discovered in certain Apple products. macOS High Sierra before Security Update 2017-001 is affected. The issue involves the "Directory Utility" component. It allows attackers to obtain administrator access without a password via certain interactions involving entry of the root user name.
https://www.wired.com/story/macos-update-undoes-apple-root-bug-patch/
https://www.exploit-db.com/exploits/43248/
https://support.apple.com/HT208331
https://support.apple.com/HT208315
https://github.com/rapid7/metasploit-framework/pull/9302