The best fix is to upgrade to 18.09.2. For those that can't do that immediately, backported versions of runc for Docker releases going back to 1.12.6 are available from Rancher at https://github.com/rancher/runc-cve. But please only do that as a temporary workaround until you can properly upgrade to 18.09.2.
Please patch if you don't 100% trust all users on your host.
Please patch if you don't 100% trust all users on your host.