OpenSSH has a vuln which allows logging in without a password. A thread.
https://www.openssh.org/releasenotes.html
It only impacts Linux distributions which ship with musl libc and PAM disabled. I think that is just Alpine Linux (all versions) and Void Linux.
It doesn’t impact Debian, Ubuntu, SUSE, Redhat or CentOS. Nor OpenWrt.
This is the technical change to fix https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482
avoid password authn bypass · openssh/openssh-portable@4353fdc