Update: Apple has acknowledged the issue and is working on it. Statement and workaround below. 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. 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. The bug is most easily accessed by going to Preferences and then entering one of the panels that has a lock in the lower...