NixOS/Pkgs 23.11 unaffected, unstable contains backdoored implementations (5.6.0, 5.6.1) but their OpenSSH sshd does not seem to link against systemd/liblzma, and the backdoor doesn't get configured in (only happens on .deb/.rpm systems).
Right, but in this case it's not even compiled it, which is arguably better than compiled in but assumed dormant :) (at least until someone actually does a full analysis of the payload).
Note that NixOS has a unique advantage in that `dlopen` is easier to analyze, but you do have to check for it. A lot of people are looking only at `ldd` and missing that they can be vulnerable at runtime.
Not affected by the latest CVE, but the author had unrestricted access to xz for 2 years, so I would say it is affected until the other contributions are proven safe (never gonna happen) or it reverts to pre-adversarial actor version.
That's one of the advantages of NixOS - viruses and mass hacks have lesser chance to function due to how different this OS is. Until it gets more popular, of course.
It's actually not an advantage. The reason why the exploit wasn't included is because the attacker specifically decided to only inject x86_64 Debian and RHEL to reduce the chances of this getting detected.