sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass (related to misinterpretation of whether a string is intended to be a password hash). For some configurations of accounts, any password between 256 and 1024 characters succeeds. An example of a platform using musl libc without PAM is Alpine Linux.
https://www.openssh.org/releasenotes.html#10.6p2
https://news.ycombinator.com/item?id=50379704
https://news.ycombinator.com/item?id=50378228
https://news.ycombinator.com/item?id=50377976
https://marc.info/?l=openssh-unix-dev&m=179388064263131&w=2
https://hachyderm.io/@damienmiller/117563026759098135
https://github.com/predkambrij/sshhole-repro
https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482
https://github.com/leonjza/sshhole-lab
https://github.com/google/goonami-scanner/pull/277
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-117552
https://alpinelinux.org/posts/2026-11-05-openssh-password-authentication-bypass/