Also, afaik firejail runs as suid, making any possible escape much more serious.
> For a server, the process exposed to the outside world runs as an unprivileged user (unbound or nobody). The process is started by a separate process running as root (as explained by @Ferroin above). The starting process is never exposed to outside.
> The same is true for Firejail. By the time the unprivileged server process starts, Firejail is already sleeping.
And I think Docker has a similar problem as mentioned in the "warning" section in [2]:
> Warning: Anyone added to the docker group is root equivalent because they can use the docker run --privileged command to start containers with root privileges. For more information see [3] and [4].