This is an educated guess, but I believe unprivileged Docker containers cannot create (user) namespaces. Hence, the vulnerability cannot be triggered, since the

This is an educated guess, but I believe unprivileged Docker containers cannot create (user) namespaces. Hence, the vulnerability cannot be triggered, since the exploit requires interaction with nf_tables, which requires (namespace) root. LXC containers and privileged Docker containers allow these namespaces to be made inside of them, whilst unprivileged Docker containers do not.