The real issue is that WebRTC ignores your proxy settings. This is obviously incorrect behaviour.
Also there's no reason to allow silent P2P connections.
If you're thinking of the bug that exposed private IP addresses to the browser, it was fixed years ago.
It's not fixed, see your addresses at https://www.privacytools.io/webrtc.html
Re:WebRTC: the future of web games
by pthatcherg on Tuesday December 27, 2016 @06:31PM
(#13267225)
If you want to force all traffic through a proxy, you must enable it using an extension, such as this one:
https://chrome.google.com/webstore/detail/webrtc-network-lim...
But having random sites doing this, didn't feel right to me.