I would recommend upgrading OpenSSH (or just disabling password auth) if you use any non-mainstream-glibc, non-OpenBSD systems - not only musl.

I don't know any in particular to be vulnerable and multiple things would probably have to come together for that to happen, but the property (a difference in crypt() behavior that Theo has known about for decades) is not unique to musl, and it's plausible that other systems are affected too.