As of January 2026, it appears that ongoing work on closing the security gap regarding process isolation between Firefox on Android and Chromium-based browsers has seen some major progress.
Following the update to Firefox 147, Site Isolation (Fission) is now enabled by default on Android devices.
Safer browsing: Added protection against side-channel attacks such as Spectre using the same Site Isolation safeguards already in use by desktop Firefox.
The lack of full site isolation has always been a common critique of GeckoView on Android. For those who strictly model for the attacks this is meant to mitigate, I think this is a step in the right direction.
Nice to know about this update but i hardly use firefox on mobile. It would be same for most of us. Also they added AI which is a turn off for most of udls.
Honestly I think is too late for them, and seeing the direction Firefox is taking I don’t think it should be recommended at all for android neither on desktop.
I can’t comment on the Android version as I lack the technical insight there. I’m seeing a split opinion, it’s either the ‘savior of Firefox’ on Android, or it’s ‘not good enough’ and lackluster version of fission. I’ll wait for the folks who know what they’re talking about before I decide on that.
However, I don’t understand the reasoning for not recommending desktop version. I realize the anti AI people are vocal, but the feature has a killswitch. If it’s optional, it shouldn’t be a factor. Does the browser have any fundamental flaws beyond that which would cause for it to be pulled as a recommendation?