scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument. NOTE: the vendor reportedly has stated that they intentionally omit validation of "anomalous argument transfers" because that could "stand a great chance of breaking existing workflows."
https://www.openssh.com/security.html
https://security.netapp.com/advisory/ntap-20200731-0007/
https://security.gentoo.org/glsa/202212-06
https://news.ycombinator.com/item?id=25005567