New Privacy setting added to Ublock stops WebRTC from revealing local IP addresses of VPN users. A security flaw in WebRTC leaks local IP addresses of users, even those using VPNs to websites from Firefox and Chrome browsers on Windows. Since disabling WebRTC stops apps and services from running, it is not recommended to do that, till now no adblocker prevented this from happening (?).
Ublock Origin extension Prevents the Leak of IP Addresses through WebRTC
Ublock Origin’s current dev version 0.9.9.3 has a Privacy option to stop this from happening. This version soon will be available on AMO and Chrome Web store when reaches stable stage.
All you need to do is, install this version of extension in Chrome or Firefox browser, visit Settings, under Privacy enable, ‘Prevent WebRTC from leaking the local IP address’.
We’ve tested this extension on Chrome Canary and Firefox 39 beta, and testing site https://diafygi.github.io/webrtc-ips/ hasn’t shown the local IP address assigned by the ISP to computer, but https://ipleak.net/ site did.
Note: Developer says this version works for Chromium-based browsers only on version 42+.