Minor Firefox security updates arrive for both Tor Browser and Mullvad Browser

If you run Tor Browser or Mullvad Browser on your computer or phone, go ahead and hit that update button. Both projects just pushed out small maintenance updates to plug a few security holes that Mozilla recently patched in Firefox.

Don’t expect to see any big visual overhaul or new features with the builds. Both just focus on under-the-hood improvements to keep things secure.

The two browsers sit on top of the same underlying Firefox ESR foundation, so whenever Mozilla patches a flaw, these privacy forks have to follow suit.

Also, considering the fact that Tor and Mullvad placed near the top of the chart when every major browser got privacy tested recently, taking ten seconds to restart your browser is about as easy as privacy maintenance gets.

Looking at the release details, version 15.0.20 updates the core codebase to Firefox 140.14.0esr and backports security fixes from Firefox 154. The Tor Project noted in its announcement that this release brings important “security updates to Firefox” alongside an updated GeckoView component on Android.

Over on GitHub, Mullvad Browser got the exact same underlying fixes, plus a small bump to 1.73.0 for its built-in uBlock Origin add-on.

It is worth noting that these small patches pop up right in the middle of a busy stretch for both dev teams. The Tor Project is coming off a huge win where it raised over $200,000 to keep private browsing alive using its very first community funding campaign.

At the exact same time, Mozilla just launched Firefox 154 with built-in AI controls and new tab management tools. Naturally, those consumer-facing bells and whistles do not make their way into privacy-focused browsers like Tor or Mullvad, but the underlying safety patches are always a top priority.

If you already have either app running, you should get a prompt to restart soon, or you can manually trigger the update from the settings menu or grab the new build from their official sites.

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