LibreWolf vs Firefox, Waterfox and Brave Head to Head

Short Answer

Run LibreWolf if you want Firefox with the telemetry, the ads and the artificial intelligence (AI) features taken out before the browser is built. In the guides we publish here, the browser question comes up more than any other.

LibreWolf is a rebuild of Firefox, and it follows upstream closely. Version 155.0-1 was published on Codeberg on 1 September 2026, the same day Mozilla released Firefox 155.0. It disables telemetry, ships uBlock Origin already configured, turns on resistFingerprinting, and blocks Digital Rights Management (DRM) playback.

Those defaults cost you something every day. LibreWolf wipes your cookies and history when you close it, so you sign in to everything again the next morning. Netflix refuses to play at all until you switch DRM back on.

Stay on Firefox if you want streaming, sync and session restore to work with no setup. Pick Waterfox for a quieter Firefox that leaves those things alone, or Brave if you would rather be on Chromium with the ad blocking built into the browser itself. Our guide to browsers without AI covers the wider field.

What LibreWolf Changes about Firefox

LibreWolf rewrites Firefox's default preferences at build time and locks many of them, so the browser arrives hardened rather than asking you to harden it. The project's own features page and its published configuration file spell out each change.

• Telemetry, crash reporting and Normandy studies are set to false and locked, so the browser makes no reporting calls to Mozilla while you use it.
• uBlock Origin is bundled with filter lists already loaded and Tracking Protection set to strict, which means ads and trackers are blocked on first launch with nothing to install.
• resistFingerprinting is on. It comes from the Tor Project uplift work. Your copy reports the same window size, timezone and theme as every other copy, so sites cannot pick you out of the crowd by those values.
• DRM playback is disabled, which stops Spotify, Netflix and Amazon Prime Video from playing until you enable it under Settings, General, Digital Rights Management (DRM) Content.
• Firefox Sync is off unless you enable it, so your bookmarks and saved passwords stay on the machine in front of you.
• Sponsored tiles and Mozilla VPN promotions are stripped from the home page, and the bundled search list leads with DuckDuckGo instead of Google.
• Every AI preference is blocked. LibreWolf sets browser.ml.enable to false and locks browser.ai.control.default to blocked, so Firefox's Smart Window, link previews and AI tab grouping never appear in the interface at all.

One item on older LibreWolf comparison lists has expired. LibreWolf removes Pocket at compile time. Mozilla shut Pocket down on 8 July 2025 and pulled the integration out of desktop Firefox, so it is not a difference between LibreWolf and Firefox today.

LibreWolf vs Firefox

Firefox collects technical and interaction data by default and shows sponsored content on the New Tab page, and LibreWolf ships with both turned off and locked. Mozilla states it plainly in the Firefox Privacy Notice: "Firefox shows content on New Tab, along with advertising to support its development. You can turn these off at any time in your browser settings."

The AI gap is narrower than most comparisons suggest. Firefox 155 ships Smart Window, an assistant Mozilla describes as optional. Its release notes offer it only to users in the USA, Canada and France. The AI Controls screen carries a single Block AI enhancements switch that covers current and future AI features. LibreWolf's edge is that the same outcome is the factory setting and is locked, so no update can quietly hand the feature back to you.

Waterfox vs LibreWolf

Waterfox is a gentler fork than LibreWolf. It strips telemetry and adds ad blocking, but it leaves your session and DRM alone, so it behaves like ordinary Firefox on the sites you already use. Waterfox describes itself as a browser "that has had its data collection and telemetry features disabled", with built in ad blocking and anonymised Domain Name System (DNS) lookups.

Readers ask about Waterfox's ownership history, and the record is public. Founder Alex Kontos announced that Waterfox had joined System1, a search advertising company, on 14 February 2020. That arrangement ended, and he wrote "I am happy to say that Waterfox is independent again" on 3 July 2023.

On AI, Waterfox has written its position down. Its published memorandum on large language models states that "Waterfox does not include large language models (LLMs) by default in the browser". It adds that "No LLM features are enabled by default". You get a Gecko browser with no assistant to switch off in the first place.

The two forks differ most on which Firefox engine they build from. Waterfox tracks Mozilla's Extended Support Release (ESR) branch. Version 6.7.0 moved it from Gecko ESR 140 to Gecko ESR 153 on 19 August 2026, and 6.7.1 followed on 26 August 2026, according to the published Waterfox changelog. Before that, the 6.6 series ran on ESR 140 as late as 6.6.17 on 21 July 2026. ESR receives Mozilla's security backports, so this is not an unpatched browser, but its web engine trails the rapid release build LibreWolf ships.

LibreWolf vs Brave

LibreWolf and Brave block the same things and disagree about method. LibreWolf uses resistFingerprinting, which works by making every LibreWolf user look identical to every other one. Brave randomizes instead, describing its approach as "making them appear subtly different to each website", a technique it calls farbling.

Brave's blocking is built into the browser rather than into an extension, so Google's Manifest V3 rules cannot weaken it. Brave also force enables Manifest V2 for uBlock Origin, AdGuard, NoScript and uMatrix, which keeps those four extensions working when Chrome drops them. Brave calls that a best effort commitment rather than a guarantee.

Brave ships an AI assistant called Leo in the browser interface. Brave's privacy policy says it does "not store or retain prompts, responses, context, or personal data on our servers" and does not use conversations for model training. If you want no assistant present at all rather than a well behaved one, LibreWolf gives you that with no settings to change.

Brave matches LibreWolf on two points people expect it to lose. Brave's help centre page on DRM protected content says Widevine is disabled by default and has to be installed before it runs. LibreWolf also ships with Widevine off. You enable the component from brave://settings/extensions before Netflix plays. Brave sync also needs no account, because the decryption key stays on your devices. If Brave against Firefox is the choice in front of you, our Brave vs Firefox comparison handles that pair on its own terms.

How Fast Security Patches Reach Each Browser

LibreWolf publishes a build within about three days of each Firefox stable release, and often on the same day. Its frequently asked questions (FAQ) page puts the window at "within three days from each upstream stable release, at times even the same day". The release list agrees. Firefox 155.0 landed on 1 September 2026, and LibreWolf 155.0-1 was published that day.

The weak point is not the build. LibreWolf has no auto-updater, and the project says so itself: it "does not have auto-update capabilities, and therefore it relies on package managers or users to apply them". A Linux user whose package manager pulls updates nightly is current. A Windows or macOS user who installed it once and forgot can sit months behind on a browser whose whole point was security.

Waterfox's lag is deliberate rather than accidental. ESR exists so that patches get backported to an older engine, so a Waterfox user on ESR 153 is patched even while missing a year of Firefox feature work. That tradeoff is reasonable, and it is a different tradeoff from LibreWolf's.

Brave rebases on Chromium continuously and publishes the pairing openly. Version 1.94.119 shipped on 2 September 2026 on Chromium 152.0.7977.76, one release after v1.94.117 on 27 August 2026, per Brave's own release notes. Of the four browsers here, only LibreWolf says it has no automatic update path. That fact should weigh more in your decision than any privacy default it flips.

What the Hardened Defaults Cost You Every Day

LibreWolf's defaults break five ordinary things, and the project documents all five in its own FAQ. Readers most often treat a hardened fork as a drop-in swap for Firefox. Then they blame the website when a login or a video fails.

1. Logins clear when you quit. To stay signed in to your bank or your email, add the site under Settings, Privacy and Security, History, Manage Exceptions. Add it before you log in, and add both the http and https versions of the domain.
2. Session restore does not work. LibreWolf states that "session restore will not work unless you preserve your browsing history", so reopening yesterday's tabs means keeping history and losing that part of the hardening.
3. Streaming fails silently until you act. Enable DRM in Settings, then grant it per site, which LibreWolf recommends over switching it on globally.
4. Some images render as stripes and some video calls fail. Canvas access is blocked until you grant it, and conferencing sites may need WebGL and autoplay enabled before the call connects.
5. resistFingerprinting changes how the browser looks and behaves. It spoofs your timezone, forces a light theme, opens at a smaller fixed window size, and suppresses alt key shortcuts. LibreWolf advises against disabling it, because every user who does shrinks the crowd the rest are hiding in.

One more error catches people out. LibreWolf runs Online Certificate Status Protocol (OCSP) checks in hard fail mode, so a slow or broken certificate server produces SEC_ERROR_OCSP_SERVER_ERROR on a site that works everywhere else. The FAQ documents a soft fail override for that. If you want the privacy without the browser rebuild, our guide to protecting your privacy online covers the settings side, and AI free apps covers the rest of the desktop.

Which One to Run

Run LibreWolf, and expect to spend an evening on exceptions. It is the only browser of the four that enforces its privacy posture at build time rather than offering it as a setting. It runs the current Firefox engine rather than a year old one, and it reached Firefox 155 parity on release day.

LibreWolf is a poor fit for two groups. If you do not install software updates by hand, the missing auto-updater turns a hardened browser into a stale one. You are safer on Firefox with Block AI enhancements switched on in AI Controls, sponsored content turned off in New Tab settings, and uBlock Origin installed. If you need banking sessions, streaming and video calls to work without configuration, run Waterfox. It gives you the telemetry removal and the no LLM policy without clearing your cookies every night.

Two things would change our answer. The first is an automatic updater for Windows and macOS. If LibreWolf shipped one, we would drop the caveat and recommend it without qualification. The second is Mozilla making Smart Window mandatory or removing the Block AI enhancements switch. That would remove the reason to fall back to Firefox, and Waterfox would become our recommendation for everyone who cannot live with LibreWolf's friction.

If you are weighing librewolf vs firefox this week, install LibreWolf alongside Firefox rather than in place of it. Add your bank and your email to the cookie exceptions list before you log in, then give it seven days. Then read our roundups of Chrome alternatives, search engines without AI and how to turn off AI Overviews to finish the job.