libssh -- Unsanitized location in scp could lead to unwanted command execution

The libssh team reports:

In an environment where a user is only allowed to copy files and
not to execute applications, it would be possible to pass a location
which contains commands to be executed in additon.
When the libssh SCP client connects to a server, the scp
command, which includes a user-provided path, is executed
on the server-side. In case the library is used in a way
where users can influence the third parameter of
ssh_scp_new(), it would become possible for an attacker to
inject arbitrary commands, leading to a compromise of the
remote target.