In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host name has shell metacharacters, and this name is referenced by an expansion token in certain situations. For example, an untrusted Git repository can have a submodule with shell metacharacters in a user name or host name.
seclists.org/fulldisclosure/2024/Mar/21
www.openwall.com/lists/oss-security/2023/12/26/4
github.com/openssh/openssh-portable/commit/7ef3787c84b6b524501211b11a26c742f829af1a
lists.debian.org/debian-lts-announce/2023/12/msg00017.html
security.gentoo.org/glsa/202312-17
security.netapp.com/advisory/ntap-20240105-0005/
support.apple.com/kb/HT214084
vin01.github.io/piptagole/ssh/security/openssh/libssh/remote-code-execution/2023/12/20/openssh-proxycommand-libssh-rce.html
www.debian.org/security/2023/dsa-5586
www.openssh.com/txt/release-9.6
www.openwall.com/lists/oss-security/2023/12/18/2