Apple has now released this update to High Sierra. (see links below)
As a side note, I was advised of this update through an email (just received prior to this writing), from the developer (Maintain) of the 3d party utility, Cocktail (11.1 is current for High Sierra). The email advised that this Apple update (10.13.2) includes "a permanent fix for the root password security flaw" and the email also provided a link to Apple's Combo Update, which the developer, Maintain, recommended using.
10.13.2 Combo Update Apple Support - Security Updates 
