What Is a WebRTC Leak in Firefox?
WebRTC stands for Web Real-Time Communication — an open technology built directly into modern browsers that enables audio calls, video conferencing, and peer-to-peer file sharing without requiring any plugin or external software. It powers tools like Google Meet, Discord web, Jitsi, and browser-based screen sharing. Firefox has supported WebRTC since version 22, making it deeply embedded in how the browser handles real-time communication.
The privacy problem with WebRTC is a consequence of how it establishes peer-to-peer connections. To connect two devices directly, WebRTC uses a process called ICE — Interactive Connectivity Establishment — which collects your device's IP addresses, including both your public IP and your local network IP. These are shared with the website or application initiating the WebRTC connection, often without any visible indication to the user.
For most users this is harmless. But for anyone using a VPN to mask their real IP address, WebRTC creates a dangerous bypass. Your VPN encrypts and reroutes your internet traffic at the network level, replacing your real IP with the VPN server's IP. However, WebRTC operates at the browser level and can bypass this tunnel entirely, exposing your real IP address directly to any website that requests it through a WebRTC connection — even if your VPN shows as fully connected and active.
Firefox's implementation of WebRTC differs from Chrome's in one important way: Firefox provides a native configuration option to disable WebRTC entirely through its about:config settings panel. This means Firefox users can fix a WebRTC leak without installing any extension, without relying on a third-party tool, and without any ongoing maintenance. It is a one-time fix that persists across browser sessions and updates.
The leak does not require you to be actively on a video call. Any website that includes WebRTC JavaScript code — even passively in the background — can trigger an IP discovery request. Some advertising networks and tracking scripts use WebRTC specifically to collect real IP addresses from users who believe they are protected by a VPN. This makes the risk more widespread than most users realise.
The good news is that Firefox WebRTC leaks are among the easiest browser privacy issues to fix. The process takes under two minutes, requires no technical knowledge, and does not break normal browsing. The only trade-off is that browser-based video calling and WebRTC-dependent applications will no longer work in Firefox after the fix — a trade-off most privacy-focused users are happy to make, especially since video calls can be handled in a separate browser if needed.
Does Firefox Leak WebRTC by Default?
Yes — Firefox enables WebRTC by default on all installations. This is not a bug or oversight; it is a deliberate design decision to ensure compatibility with the growing ecosystem of browser-based communication tools. When you install Firefox fresh, WebRTC is active and will expose your IP address to any site that requests it unless you take action to disable or restrict it.
Mozilla has acknowledged the privacy implications of WebRTC and has provided the native about:config toggle specifically to address this concern. Unlike Google Chrome, which requires users to install an extension or navigate complex flag settings to restrict WebRTC, Firefox gives users a single, clear configuration option that fully disables WebRTC at the browser engine level.
It is worth noting that even privacy-enhancing Firefox configurations such as private browsing mode, Firefox Focus settings, and tracker blocking do not disable WebRTC. The about:config fix described below is the only reliable method to fully prevent WebRTC IP exposure in Firefox. Extensions and VPN-based WebRTC blocking provide partial protection but are not as reliable as the native configuration change.
How to Fix a WebRTC Leak in Firefox – Step by Step
Open the Firefox Configuration Panel
Type about:config into the Firefox address bar and press Enter. You will see a warning page that says "Proceed with Caution" — this is standard for any advanced Firefox settings. Click "Accept the Risk and Continue" to proceed. This page gives you access to Firefox's full internal settings and is safe to use.
Search for the WebRTC Setting
In the search bar at the top of the about:config page, type: media.peerconnection.enabled — this is the specific setting that controls whether WebRTC is active in Firefox. You should see a single result appear below the search bar. This is the only setting you need to change to disable WebRTC entirely.
Disable WebRTC
The current value will show as "true" — meaning WebRTC is enabled. Double-click on the row to toggle the value from "true" to "false". The value in the right column will change and the row will briefly highlight to confirm the change. No restart is required — the change takes effect immediately.
Verify the Change
The value next to media.peerconnection.enabled should now show "false" in bold text. Bold text in about:config indicates a value that has been changed from its default — this is the expected appearance after disabling WebRTC. If the value still shows "true", double-click it again to toggle it correctly.
Run the Leak Test Again
Return to the top of this page and run the WebRTC leak test again. If the fix has worked correctly, the test should now show no WebRTC IP detected. This confirms that Firefox is no longer exposing your IP address through WebRTC to any website or service.
Optional — Enable Additional Privacy Protection
While in about:config, search for privacy.resistFingerprinting and set it to "true" if it is not already. This setting enables a broader set of fingerprinting protections that go beyond WebRTC, making it harder for websites to track your browser across sessions. It is recommended for any user who has taken the time to disable WebRTC.
Optional — Restrict WebRTC Without Fully Disabling It
If you want to keep WebRTC functional for video calls but prevent IP leaks, search for media.peerconnection.ice.default_address_only and set it to "true". This tells Firefox to only use your default network interface for WebRTC connections, preventing local IP addresses from being exposed while keeping WebRTC active. This is a middle-ground option for users who need browser-based video calling.
Test After Every Firefox Update
Major Firefox updates occasionally reset about:config values, particularly after significant version upgrades. After any major Firefox update, return to about:config and confirm that media.peerconnection.enabled is still set to "false". This takes 30 seconds and ensures your protection remains in place.
Firefox WebRTC Leak – Does Your VPN Help?
A VPN alone is not sufficient to prevent a Firefox WebRTC leak. This is one of the most common misconceptions among VPN users. The VPN routes your network traffic through an encrypted tunnel, but WebRTC operates within the browser itself and can bypass that tunnel to directly expose your real IP. This is not a flaw in any specific VPN — it is a fundamental architectural issue with how WebRTC works in all browsers.
Some premium VPN providers include browser extensions that block WebRTC leaks alongside their main client. NordVPN, for example, offers a browser extension that adds WebRTC leak protection on top of the VPN tunnel. However, even with these extensions, the native about:config fix in Firefox remains the most reliable single method for preventing WebRTC IP exposure.
The most effective approach for maximum privacy is layered protection: disable WebRTC natively in Firefox via about:config, use a reputable VPN with a kill switch enabled, and consider installing uBlock Origin which can also restrict WebRTC in certain configurations. Any single one of these provides meaningful protection; all three together create a robust privacy setup.
If you use Firefox as your primary browser and privacy is important to you, the about:config fix should be the first thing you configure on any new Firefox installation — before logging into any accounts or visiting any websites. It is a permanent, maintenance-free change that protects every browsing session from that point forward.
Firefox WebRTC vs Chrome WebRTC – Which Is Easier to Fix?
Firefox is significantly easier to fix for WebRTC leaks than Chrome or Edge. Firefox's native about:config panel provides a single, clear toggle that fully disables WebRTC at the engine level. Chrome does not offer an equivalent native setting — Chrome users must install a third-party extension or use Chrome flags, both of which are less reliable and may stop working after browser updates. For the full Chrome fix process, see our WebRTC leak fix guide for Chrome.
Brave browser comes with built-in WebRTC IP protection enabled by default, making it the most privacy-friendly choice out of the box. Safari has limited WebRTC exposure compared to Chrome but does not give users direct control over WebRTC settings. For users who want the most control over their browser privacy settings, Firefox remains the best choice among mainstream browsers.
If you use multiple browsers, it is worth testing WebRTC leaks in each one separately. A fix in Firefox does not protect you in Chrome or Edge. Use the test at the top of this page in each browser to check your current status, and follow the browser-specific guides on this site to fix any leaks you find.
Yes — Firefox for Android also has an about:config panel accessible by typing about:config in the address bar. The same setting — media.peerconnection.enabled — exists on mobile Firefox and can be set to false using the same process. This is particularly relevant for Android users who use a VPN on their mobile device, as WebRTC leaks can expose your real IP on mobile networks just as on desktop.