Earlier today, Apple has issued an emergency update for macOS High Sierra to address a bug that exposed the passwords of encrypted APFS volumes via the password hint feature.

The bug was discovered earlier today by Brazilian security researcher Matheus Mariano of Leet Tech, who also published the YouTube video embedded below.

https://www.bleepingcomputer.com/news/apple/apple-issues-emergency-patch-to-fix-password-leak-in-disk-encryption-utility/