This is not a bug. This is the the entire design architecture's intent for modern JS application execution based "web". If this was the correct choice for the web then this should not be a problem at all. But we all know it is. The architecture choice forces this. Until we stop arbitrarily executing random third party code this will always happen. And the consequences will get worse and worse as more bare metal features are exposed in to browsers JS virtual machines.
Be the change in the world you want to see. Turn javascript off. Use real native applications that cannot change underneath you.