Glossary · VPN & tunneling

WebRTC leak

Also calledwebrtc ip leak

Definition

A WebRTC leak exposes your real IP to a website via the browser's WebRTC API — even when a VPN is active — because WebRTC uses STUN outside the tunnel.

Explanation

In depth

WebRTC (Web Real-Time Communication) is the browser API behind video calls and peer-to-peer connections. To find the best path to a peer, WebRTC uses STUN servers, which reveal all your device's IP addresses — including the real one, before the VPN tunnel wraps it. This is a browser-level leak, not a VPN-client bug. Fix by disabling WebRTC in browser settings, using a WebRTC-blocking extension, or ensuring your VPN client patches the browser to force WebRTC through the tunnel. Web proxies do not have this problem because they only handle the current tab — WebRTC on other tabs is unaffected, and the destination in the proxied tab sees only the proxy IP.

Related terms

VPNA VPN is a service that routes every network request from your device through an encrypted tunnel to a remote server.DNS leakA DNS leak happens when your device sends DNS lookups outside the VPN tunnel — revealing which sites you are visiting even though the traffic itself is encrypted.IPv6 leakAn IPv6 leak happens when your VPN tunnels IPv4 traffic but lets IPv6 traffic bypass the tunnel — exposing your IPv6 address to destinations.IP addressAn IP address is a numeric identifier assigned to each device on a network — how packets know where to go.

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