Just a few hours before the release of High Sierra, ex-NSA hacker Patrick Wardle publicly disclosed the details of a separate critical vulnerability that allows installed apps to steal passwords and secret data from the macOS keychain.
The good news is that Apple released a supplemental macOS High Sierra 10.13 update on Thursday to addressed both the issues. Mac users can install update from the Mac App Store or download it from the Apple's Software site.
It should be noted that just installing the update would not solve the APFS password disclosure issue. Apple has published a user guide on the password disclosure bug, which you should follow to protect your data.