Wow, this is a bad one. On Macs running the latest version of High Sierra (10.13.1 (17B48)), it appears that anyone can log in just by putting “root” in the user name field in a certain place. This is a huge, huge problem. Apple will fix it probably within hours, but holy moly. Do not leave your Mac unattended until this is resolved.
Copy and paste this URL into your WordPress site to embed
Copy and paste this code into your site to embed