Borg clients can access the whole storage box through SFTP

This appears to give access to the whole storage box: sftp -P23 u236610@u236610.your-storagebox.de

It works from the root account on any borg client. Seeing as /.ssh/authorized_keys on the storage box has the following for each borg client, it is likely unintentional to give borg clients this level of access:

command="/usr/bin/borg serve --restrict-to-path backup/<hostname>",no-pty,no-agent-forwarding,no-port-forwarding,no-X11-forwarding,no-user-rc [...]