What Is WebRTC?
WebRTC stands for Web Real-Time Communication. It's an open-source technology built directly into modern web browsers that enables real-time peer-to-peer communication. This powers features like:
- Browser-based video and voice calls (Google Meet, Discord web, Facebook Messenger)
- Peer-to-peer file sharing
- Live streaming with low latency
- Screen sharing in web applications
- Real-time gaming in the browser
WebRTC was developed by Google and became a W3C standard. It's supported natively in Chrome, Firefox, Edge, Safari, and Opera — no plugins or extensions required. This ubiquity is both its strength and its privacy weakness.
How WebRTC Works (And Why It's a Problem)
To establish a peer-to-peer connection, WebRTC needs to discover your network configuration. It does this through a process called ICE (Interactive Connectivity Establishment), which gathers "candidates" — potential network paths for communication.
During this process, WebRTC queries your device for all available network interfaces and their associated IP addresses. This includes:
- Local IP addresses: Your private network address (like 192.168.1.100)
- Public IP addresses: Your real, internet-facing IP address — the one your VPN is supposed to hide
- Reflexive candidates: IP addresses discovered through STUN servers, which reveal your actual public IP
Here's the critical problem: WebRTC makes these requests at the browser level, often bypassing system-level network configurations including VPN tunnels. A website can use simple JavaScript to trigger WebRTC's ICE candidate gathering and read your real IP address — all without your knowledge or consent.
The JavaScript code to exploit this is trivially simple. Any website can create a WebRTC peer connection, listen for ICE candidates, and extract your real IP address in milliseconds. This happens silently in the background — no permission prompts, no notifications, no visible indicators.
How a WebRTC Leak Exposes Your Real IP Address
When you use a VPN, your traffic is routed through the VPN server, and websites see the VPN server's IP address instead of yours. But WebRTC operates independently from the VPN tunnel. When a website triggers WebRTC's ICE gathering:
- Your browser queries all network interfaces for IP addresses
- It contacts STUN servers (external servers that tell your browser its public IP)
- The STUN request may go outside the VPN tunnel, revealing your real IP
- Even if the STUN request goes through the VPN, local candidates still reveal your private IP
- The website collects these IP addresses through JavaScript
The result: a website sees both your VPN's IP address (from regular traffic) AND your real IP address (from WebRTC). It can trivially determine that you're using a VPN and identify your actual location.
You can check if your browser is vulnerable right now using our WebRTC Leak Test.
WebRTC Leak vs. DNS Leak: What's the Difference?
Both WebRTC leaks and DNS leaks compromise your privacy when using a VPN, but they expose different types of information through different mechanisms:
| Aspect | WebRTC Leak | DNS Leak |
|---|---|---|
| What's exposed | Your real IP address | Your browsing activity |
| Who can see it | Any website you visit | Your ISP and DNS provider |
| How it happens | Browser JavaScript API | DNS queries bypass VPN tunnel |
| What it reveals | Location, ISP, identity | Every website you visit |
| Fix location | Browser settings/extensions | VPN/OS/network settings |
Both types of leaks can occur simultaneously. A VPN that protects against DNS leaks might still allow WebRTC leaks, and vice versa. That's why you should test for both: use our DNS Leak Checker and WebRTC Leak Test together.
How Different Browsers Handle WebRTC
Each browser handles WebRTC differently, and some are more vulnerable to leaks than others:
Google Chrome
Chrome has WebRTC enabled by default with no built-in way to disable it through the settings UI. Chrome is the most vulnerable browser to WebRTC leaks because it aggressively gathers ICE candidates and shares them with requesting websites. The only way to control WebRTC in Chrome is through extensions like WebRTC Leak Prevent or uBlock Origin. See our Chrome WebRTC leak fix guide.
Mozilla Firefox
Firefox is the most privacy-friendly mainstream browser for WebRTC. You can completely disable WebRTC through about:config by setting media.peerconnection.enabled to false. Firefox also respects privacy settings more consistently and doesn't share local IP addresses as readily as Chrome. See our Firefox WebRTC leak fix guide.
Safari
Safari has limited WebRTC support and is more conservative with IP address exposure. Apple has implemented stricter privacy controls that reduce WebRTC leak risk. However, Safari isn't immune — it can still leak under certain conditions, especially with legacy WebRTC implementations.
Microsoft Edge
Edge is based on Chromium (the same engine as Chrome) and inherits Chrome's WebRTC behavior. This means Edge is equally vulnerable to WebRTC leaks. The same Chrome extensions work in Edge, and the same risks apply.
Brave
Brave browser, despite being Chromium-based, includes built-in WebRTC leak protection. By default, Brave prevents websites from accessing your real IP through WebRTC. You can configure this in Brave's Shield settings. This makes Brave one of the better choices for privacy-conscious users who don't want to install additional extensions.
Who Is at Risk from WebRTC Leaks?
Anyone using a VPN for privacy is at risk if their browser leaks WebRTC data. But some groups face greater consequences:
- Journalists and whistleblowers whose real location could put them in danger
- Users in countries with internet censorship who could face legal consequences for accessing blocked content
- Remote workers accessing company resources through VPNs who may inadvertently expose their network
- Travelers trying to access region-locked content whose real location is revealed
- Privacy-conscious individuals who rely on VPNs to prevent ISP tracking and targeted advertising
How to Protect Yourself from WebRTC Leaks
There are three main approaches to preventing WebRTC leaks:
- Disable WebRTC entirely in your browser. This is the most secure option but prevents browser-based video calls. Firefox makes this easy; Chrome requires an extension.
- Use a browser with built-in protection like Brave, which blocks WebRTC leaks by default without disabling the feature entirely.
- Use a VPN with WebRTC leak protection. Some VPNs specifically handle WebRTC traffic and prevent IP exposure at the network level.
For detailed, browser-specific instructions, see our guides for fixing WebRTC leaks in Chrome and fixing WebRTC leaks in Firefox.
Regardless of which approach you choose, always verify the fix is working by running our WebRTC Leak Test after making changes. If you also want to check for DNS leaks, combine this with our VPN DNS Leak Test.