This Web Security lecture by Feross Aboukhadijeh has a great example of Zoom's zero-day from 2019 that allowed anyone to force you to join a zoom meeting (and even cause arbitrary code execution), using a local server:
It's not clear to me from Google's proposal if it also restricts access to localhost, or just your local network - it'd be great if it were both, as we clearly can't rely on third parties to lock down their local servers sufficiently!
edit: localhost won't be restricted:
"Note that local -> local is not a local network request, as well as loopback -> anything. (See "cross-origin requests" below for a discussion on potentially expanding this definition in the future.)"
https://www.youtube.com/watch?v=wLgcb4jZwGM&list=PL1y1iaEtjS...
It's not clear to me from Google's proposal if it also restricts access to localhost, or just your local network - it'd be great if it were both, as we clearly can't rely on third parties to lock down their local servers sufficiently!
edit: localhost won't be restricted:
"Note that local -> local is not a local network request, as well as loopback -> anything. (See "cross-origin requests" below for a discussion on potentially expanding this definition in the future.)"