Huh? The exploit allows remote website you visit ends up having access to stuff bound to localhost. If a localhost website has access to other localhost stuff, it isn't as much of a big deal.

>The point of rbndr is that it switches between resolving to a remote address and to a local address, which is an entirely legitimate thing - https://owa.example.com for most companies will do exactly this when you move between the corporate network and the public internet.

IMO it's worth blocking it, and only allowing that behind a flag or a custom whitelist that the user maintains. Enterprises can easily do that.