This is particularly interesting because in a lot of deployments, nginx sits out in front of a lot of other stuff as a load balancer, where it is nicely exposed.<p>You REALLY should be using multiple boxes if you're running load balancers (especially sw load balancers) with some kind of heartbeat failover. That way you can upgrade single boxes easily, and are ok in case one of them dies. With a bug of this severity, you won't have time to test the patch, so it's probably best to upgrade one at a time in production.<p>Remember, even if you're running Apache or something else for your actual web server, you can easily have something like nginx sitting in front as a proxy/load balancer. Often in front of your security monitoring devices... and you may have forgotten about it.