Firefox 126: Telemetry, privacy feature, and security fixes

Martin Brinkmann
May 14, 2024
Updated • May 14, 2024

Mozilla plans to release Firefox 126.0 Stable later today. The new version of Firefox is a smaller release, as it makes just a few changes. Noteworthy are improvements to the browser's copy without site tracking feature, support for AV2 hardware decode acceleration on M3 Macs, and new search Telemetry.

Tip: To check the installed Firefox version, select Menu > Help > About Firefox on desktop systems.

Mozilla updates all development editions and Firefox ESR at the same time. Here are the new versions:

  • Firefox 115.11 ESR
  • Firefox 127 Beta and Dev
  • Firefox 128 Nightly
  • Firefox 126 for Android

Executive Summary

  • Firefox 126 addresses security issues in the browser.
  • Support for zstandard compression content encoding, which should improve performance on sites such as Facebook.
  • New Telemetry to aggregate searches based on "20 high-level content types" such as sports or business.
  • Mozilla pulled the URL Paste feature introduced in Firefox 125 because of performance issues.

Firefox 126.0 download and update

Updates are installed automatically by default. The new Firefox 126 update will therefore be installed automatically on most systems. Firefox users may speed up the installation by opening Firefox Menu > Help > Firefox, but only after the official release later today.

Here are the official download locations:

Firefox 126.0 changes

Copy (Link) Without Site Tracking

Copy Without Site Tracking and Copy Link Without Site Tracking enable users to copy URLs without tracking parameters. This feature has been available for a while. The update introduces support for nested URLs and extends support, so that over 300 additional tracking parameters are now stripped when copying links using this feature in Firefox.

New Search Telemetry

Mozilla Firefox creates aggregate counts of broad category searches to "broadly inform search feature development". The 'categories are based on 20 high-level content types, such as "sports", "business", and "travel"'.

Mozilla notes that the data is not associated with individual users and that it is collected using OHTTP to remove IP addresses. Furthermore, profiling will not be performed and data won't be shared with third-parties.

Tip: Firefox users who do not want this can se to False on about:config.

Other changes and fixes

  • Firefox Translations supports Catalan now.
  • AV1 hardware decode acceleration supported on M3 Macs.

Developer changes

  • The zstd directive of the Content-Encoding HTTP header is now supported, allowing decoding of server-sent content encoded with the Zstandard compression algorithm.
  • IDBFactory.databases() is now supported for enumerating available IndexedDB API databases
  • IDBTransaction.durability can now be used for querying the transaction durability hint that the transaction was created with
  • The URL.parse() static method is now supported for creating URL objects.
  • The Screen Wake Lock API is now supported. This allows web apps to request that the screen is not dimmed or locked.
  • All RTCIceCandidate properties and methods are now supported and match the specification, with the exception of unimplemented properties: relayProtocol and url.
  • The Element.currentCSSZoom read only property is now supported for getting the effective CSS zoom of an element.
  • The ability to define states for custom elements and match them using CSS selectors is now available by default.
  • The Selection.direction property is now supported for indicating the direction of a range.
  • The marquee events bounce, finish, and start have been removed from HTMLMarqueeElement
  • The commands.onCommand event now passes the tab argument to the event listener.
  • The runtime.MessageSender type now includes the origin property.
  • The "webRequestAuthProvider" permission is now supported.
  • The options_page manifest key is provided as an alias of the options_ui key.

Enterprise changes

  • TranslateEnabled policy is now available.
  • Preferences policy was update to allow setting privacy.userContext.enabled and privacy.userContext.ui.enabled, which handle Containers functionality.
  • Locking the Proxy policy locks all options, even if no values are changed.
  • Tabs from other devices no longer shows in Firefox View if Accounts are disabled.

Security updates / fixes

  • Firefox 126 addresses 16 unique security issues rated high or lower. No exploits in the wild.
  • Firefox 115.11 ESR fixes 6 unique security issues rated high or lower. No exploits in the wild.


Firefox 127 and Firefox 115.12 ESR will be released on. The next Firefox ESR version is Firefox 128 ESR, which will be released on July 9, 2024.

Recent Firefox news and tips

How to enable Tab Previews in Firefox

Additional information / resources

Closing Words

Firefox 126 is a smaller release. It is still an important update, as it addresses security issues in the browser. Mozilla had to pull two features that it introduced in recent versions of Firefox. Firefox 127 will see the introduction of bounce tracking protection.

Now you: what is your take on this release?

Article Name
Firefox 126: Telemetry, privacy feature, and security fixes
Firefox 126 fixes security issues in the web browser, adds Telemetry, and improves a privacy feature when copying links or URLs.
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  1. john said on May 22, 2024 at 9:32 am

    in firefox 127 they’re going to remove the flag:


  2. Tim said on May 18, 2024 at 8:34 am

    I like Firefox, but why don’t they focus on requested features rather than stuff like telemetry? In what way will it improve the browser? Why is their information about it so unclear?

    1. Jo said on May 22, 2024 at 5:14 pm

      because they don’t want to because it’s not on your side. They can just excrete some words to pacify a captive userbase again and again and again and remain unmotivated to stop slurping from the inexhaustible vat of stupidity and cowardice.
      You gotta either just say no, or keep asking this same question of why the next time and the next time and the next time; self autonomy is a… choice. They will tell you no when told to stop but many users can’t due to weak minds, simple.

  3. Tachy said on May 17, 2024 at 5:29 am

    “telemetry” and “privacy” huh?

    1. Paul said on May 17, 2024 at 11:10 am

      Totally agree, that’s why people must use Google Chrome. A lot of telemetry and tracking that can not be disabled and no privacy whatsoever.

      1. Allwynd said on May 18, 2024 at 6:51 am

        Or use Brave, Yandex, Ungoogled Chromium.

  4. AeroKing said on May 16, 2024 at 7:16 am

    Martin, i believe r3dfox deserves a coverage, especially now that the Firefox for the Win 7 is approaching the EoL phase

    1. Tom Hawack said on May 16, 2024 at 12:08 pm

      @AeroKing, r3dfox brought to my attention by your comment. Seems an interesting perspective by itself and even more when the Firefox115 ESR branch will come to an end (September 2024) and be followed by a non Windows 7 compatible ESR.
      I found more info here :
      Eclipse r3dfox, a modern Firefox based web browser for Windows 7! []

      Personally several questions arise concerning full compatibility with Firefox, mainly perhaps Group Policies and Autoconfig.

      @Martin, I think as well that this is worth coverage or at least an in-depth article.

  5. MartyK said on May 15, 2024 at 11:20 pm

    The update to 126.0 horks WordsWithFriends. After loading the board it pops up a dialog box that says “an error occurred”. Worked fine in 125.0.2 an hour ago. Tried to put 125.0.2 back in place and it just consumes 100% of the CPU for five minutes and then becomes “unresponsive”. Tried multiple earlier versions of FF as well. Same response. Seems this upgrade can not be downgraded to previous versions.

    WWF still works with Safari and Chrome, btw.

  6. Allen BJ said on May 15, 2024 at 3:44 pm

    Firefox is a god-send and always will be.
    Just like everything today being monopolised, i.e. all browsers are chromium. Then you have epic games unreal engine 4/5 being used everywhere with its constant stuttering and hitching mess.
    And of course all the other monopolies including microsoft, amazon, apple, KFC, BK, McCrap, etc, etc.

    Firefox is a blessing with its own in-house geko engine and all the other variants such as LibreWolf and Tor.

    1. Tom Hawack said on May 15, 2024 at 11:03 pm

      I entirely agree. I no longer loose my time responding to those who spit on Firefox. Critics, constructive critics are always welcomed, nothing is perfect, but not this sort of irrational hatred which needs to follow a crowd of haters to relieve their nerves.

  7. Rex said on May 15, 2024 at 3:23 am

    Always fun to see Firefox fanboys reactions to the constant enshittification of this browser that’s been going on since version 4, 2011. Or to see someone declare that they are ditching the browser due to the latest introduced crap. Oh really, I mean WTF were you doing all these years as it kept degrading the user experience and privacy while claiming to be their champion?

    1. Shaggy said on May 15, 2024 at 12:14 pm

      Ublock Origin works best on Firefox. Firefox works best on my Ryzen while watching YouTube, with all chromium-based browsers the fans are way louder. Firefox won’t use manifest v3. The choice is easy.

    2. CopeSeetheDilate said on May 15, 2024 at 10:12 am

      Firefox: One button to turn of all Telemetry
      Chrome: Cannot opt out.


    3. bruh said on May 15, 2024 at 10:08 am

      Let’s see, you can turn off/disable most of the crap, and then it’s still a highly customisable and decently useable browser? More customisable than any chromium doodoo you might be wanting to shill.

    4. Anonymous said on May 15, 2024 at 9:21 am

      The thing is, no matter how bad Firefox appears in your opinion, I would rather chainsaw my left testicle off than use Chrome. Chrome is just pure spyware.

      1. Tom Hawack said on May 15, 2024 at 11:19 pm

        In my view Google and a few other ones are similar to an invading army in that they invade the grounds of our very privacy. Worshipers of an enemy are plain collaborators. The final straw has always been collaborators denouncing patriots. Collaborate if you wish, but at least silently. Denouncing Firefox as the enemy is relevant of either dishonesty or of blindness. Let GAFAM companies go to hell by kicking them out appropriately.

      2. Herman Cost said on May 15, 2024 at 2:09 pm


  8. TetraCoz said on May 15, 2024 at 12:14 am

    Small update? Enough to broke custom css again.

  9. borf said on May 14, 2024 at 10:17 pm

    The search telemetry talked about here is only applicable to anyone who has checked the ‘allow’ boxes under Settings – Privacy and Security – Firefox Data Collection and Use.

    I haven’t. So this is a non-issue.

    1. Martin Brinkmann said on May 15, 2024 at 7:04 am

      Also worth noting, this Telemetry feature is only enabled for users from the U.S. according to Mozilla.

      1. Andy Prough said on May 15, 2024 at 10:58 pm

        >”this Telemetry feature is only enabled for users from the U.S.”

        I wonder if it violates Europe’s privacy regulations?

        It’s stuff like this that keeps driving me to continue using older Firefox’s cousin Pale Moon as much as I possibly can. No telemetry, no real interest in gathering up data on users at all.

  10. groovy said on May 14, 2024 at 7:53 pm

    Firefox is like a walking zombie. Its brain is rotting day by day.

  11. Some1 said on May 14, 2024 at 6:37 pm

    “Mozilla pulled the URL Paste feature introduced in Firefox 125 because of performance issues.” Yet again another botched useless feature.

    v125 had the bug in “Block dangerous downloads” that corrupted some downloaded files that were harmless.

    I am a huge Firefox fanboy, but come on Mozilla! You are making it very hard to stick with Firefox!

    1. bruh said on May 15, 2024 at 10:11 am

      “Yet again another botched useless feature.”

      Actually stripping trkparms and stuff like that from URLs is not useless and once they sort it out, should be decent. Some extensions have tried and failed to do the same thing. They need to make it reliable enough to turn on for clicking links not just copy/pasting. Ever been to ebay recently or another such site which abuses shoving a million miles of crap to what should be a very short URL?

  12. bruh said on May 14, 2024 at 6:23 pm

    I’m sorry you’re “aggregating searches”? What?

    Is this for the end user’s benefit, I don’t even understand what it means!

    “Copy (Link) Without Site Tracking” – can we click without site tracking? That would be actually useful and would render some old extensions surpassed and obselete.

  13. George said on May 14, 2024 at 6:08 pm

    Prior to update-> was set to False

    After update-> was still set to False

    so is this the only change that was needed?

    1. Alex said on May 15, 2024 at 1:16 am

      Disable telemetry in Options completely.

      No reason to disable only some part of it.

  14. Herman Cost said on May 14, 2024 at 4:47 pm

    It turns out that at least in my setup, after the FF 126 update the default setting in about:config for was already ‘false’. Perhaps the reason for that is that I already have all Firefox data collection settings disabled (however, I do have certain other telemetry settings disabled in about:config so its hard to be sure as to why the FF search change in the update did not affect me.)

    I do note that in Mozilla’s release notes, including the ‘read more’ section and accompanying ‘step by step guide’ to change your search data collection settings, they did not provide users with the info regarding the about:config change which Martin provided in his Tip. But maybe it is not needed if you simply turn off data collection in settings.

    In nacy case, the improvements to the ‘copy without site tracking feature’ are welcome.

    1. Haakon said on May 14, 2024 at 8:03 pm

      “ to False”

      Already false for me, too; I never set it manually.

      It could be via disabled settings under Data Collection in Privacy & Security or a “”DisableTelemetry”: true” policy, that policy having been implemented a long time ago for any Firefox used on any of my systems.

      I don’t know (or care) if both are needed for the job, but I’m keeping it that way as it presents no issues.

      Shout out to Martin: Thanks! Your work, as always, is greatly appreciated.

  15. George said on May 14, 2024 at 4:47 pm

    Thanks for the tip. That telemetry setting was already set to false here.

  16. John G. said on May 14, 2024 at 4:09 pm

    How to install FF ESR in Ubuntu and its branches with PPA:

    sudo add-apt-repository ppa:mozillateam/ppa
    sudo apt update
    sudo apt install firefox-esr

    With Snap:

    sudo snap install firefox –channel=esr/stable

    And you will enjoy the best face of Firefox.
    Never regret yourself, you know.

    1. A said on May 14, 2024 at 9:18 pm

      Unfortunately, the last good version of Firefox was Firefox 3.6.x, after that it gradually became more of a POS. Each time a new version releases and I read all the toxic changes they implement, like removing of customization and implementation of spying, I think to myself “this cannot get any worse”, then the next version of Firefox releases and it’s even worse.

      Firefox is a dead trash. The future is Blink – Brave, Vivaldi, Yandex, etc. It would have been good to have a competing rendering engine, but Mozilla are just blowing their opportunity, so much so, that they don’t even deserve to be pitied.

      1. TelV said on May 16, 2024 at 5:59 pm

        Have a look at Floorp:

        I’ve been using for a year already and no complaints so far…

  17. InsaRa said on May 14, 2024 at 2:25 pm

    Mozilla Firefox creates aggregate counts of broad category searches to “broadly inform search feature development”. The ‘categories are based on 20 high-level content types, such as “sports”, “business”, and “travel”‘.


    Firefox users who do not want this can se to False on about:config.

    I still have it to false, without editing

  18. Tom Hawack said on May 14, 2024 at 12:42 pm

    “Firefox users who do not want this [New Search Telemetry] can set to False on about:config.”
    Telemetry, telemetry, telemetry …
    It’d be done immediately should I be updating Firefox to version 126. I’ll be comfortable by updating ESR from 115.10.0 to 115.11.0
    Thanks as always @Martin for the review.

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