Version 10.6p2 of OpenSSH has been released with a workaround for a critical vulnerability that affects Linux systems that use musl libc with PAM disabled, such as Alpine Linux. OpenSSH developer Damien Miller said:

If you operate a Linux system that uses musl libc without PAM (Alpine Linux is one example) then stop reading and set PasswordAuthentication=no or disable SSH for these systems IMMEDIATELY.

This vulnerability does not exist on non-Linux systems, Linux/glibc systems and Linux systems that use PAM for password authentication.

We consider the root cause of this bug to be outside OpenSSH itself, but we're in a good position to deliver a mitigation quickly.

The Alpine Linux project has announced that it will be backporting the OpenSSH fix "all the way back to Alpine 3.16", which was released in May 2022.