Firefox blocks F-Secure Browser Protection Add-on

Mozilla[German]Brief information for users of the Firefox browser in Windows, who also have the F-Secure antivirus solution in use. Since March 18, 2022, the browser has blocked the F-Secure Browser Protection add-on in versions up to 4.0.52, allegedly for violating Mozilla's add-on guidelines.


A reader info

It was a short message from a German blog reader reader via Facebook that reached me today – I'm only now getting around to briefly rehashing it. The relevant text of the message was:

Do you know anything about Firefox rejecting the F-secure add-on? I have F-Secure on my laptop.

Firefox blockiert F-Secure Browser Protection Add-on
Click to zoom

Included was the screenshot above showing the Firefox display. The user is informed that the Firefox browser add-on "Browsing Protection by F-Secure" has been disabled to protect the user. The reason given is that the add-on violates Mozilla's add-on policy. The Firefox browser then disables the add-on automatically. In the screenshot above, you can see that the disabling occurred on March 18, 2022 and is valid until version 4.0.52. From this I conclude that the add-on was accepted by Firefox before that date.

Entries in the F-Secure forum

I did some quick research and found what I was looking for in the F-Secure forums, for example in this thread. With date March 18, 2022, another user reports that the Firefox browser add-on "Browsing Protection by F-Secure" has been disabled:

Mozilla Firefox blocking Browsing Protection by F-Secure addon

I had the F-Secure addon (version 3.0.27) installed and today Mozilla blocked and disabled it, stating:


"Browsing Protection by F-Secure has been blocked for your protection.

Why was it blocked?

This add-on violates Mozilla's Add-on Policies.

This add-on violates Mozilla's add-on policies by executing remote code and insufficient user data handling and protections.

What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.

Versions blocked: 0 to 4.0.52.

Blocked on Mar 18, 2022.

Firefox blocks F-Secure Browser Protection Add-on


In the thread there are confirmations of further affected persons – further hits are here, here and here. And it doesn't seem to have been the first occurrence (here's an entry from 2021). 

F-Secure is aware of the issue

In the meantime, an F-Secure moderator has written in the forum that the problem is known. They are working with Mozilla to find a solution:

Hi @mrxfsec @needsomeusername @radetzky @ruudvl @MagDux @Ronnie74 @Beecee @Flockle

We are aware of this issue on the Windows version of our consumer and corporate EPP products.

We are currently working with Mozilla to solve this issue. Meanwhile, we recommend that you use either Microsoft Edge or Google Chrome browser until the issue has been fixed.

We already published a KB article about this issue and you can read more here 

You can subscribe to our Status page to get notified on incident reports and when they get resolved.

Thanks for your patience and understanding.

The KB article states that the problem with Firefox occurs only on Windows when using the following F-Secure products:

  • F-Secure Home products: F-Secure TOTAL, F-Secure SAFE, and F-Secure Internet Security
  • F-Secure Business products: F-Secure Elements Endpoint Protection, F-Secure Elements EPP for Computers, F-Secure Elements EPP for Servers, F-Secure Client Security, F-Secure Server Security

The browser extension is a plug-in application that ensures the user's security while browsing. The Browsing Protection extension is currently not available for Mozilla Firefox. For this reason, the Safe Browsing and Banking features do not fully work when using the Firefox browser at the moment. F-Secure says it is working with Mozilla to resolve this issue. In the meantime, the F-Secure folks recommend users to use either Microsoft Edge or Google Chrome until the issue is resolved.

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6 Responses to Firefox blocks F-Secure Browser Protection Add-on

  1. Ulli says:

    I guess, Firefox has shot himself in the knee by this:
    I have to inform now a lot of people to no further use Firefox, as log as the (well paid) F-Secure- add-on is blocked.
    I guess, they all will be quite unhappy about this, and if the blocking lasts for longer,
    they will prefer to stick with the newly experienced Browser Chrome.

    A good example how to make oneself dispensable…..

    • sadra says:

      'Brave' doesn't allow F-secure either but does allow 'you' to let it through

      I'm at least a 20 year Firefox fan, getting old and don't like changes now lol

      They send me email asking me to fill in survey on how they did?
      -they have done 'nothing'.
      Seriously they could have sent out this: "We are currently working with Mozilla to solve this issue. Meanwhile, we recommend that you use either Microsoft Edge or Google Chrome browser until the issue has been fixed."

  2. Tonke says:

    Add-on is fixed! It was just a missing link to the privacy policy.

    • guenni says:

      Got the feedback from German reader, that the Add-on still can't be installed. There are more issues.

  3. Wim says:

    re-install of the fsecure plugin worked here (firefox 98.0.2). Plugin version 4.1.11

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  5. sadra says:

    Went into F-secure settings and clicked on the "install extension for Firefox" and then gave Firefox permission to take over my computer 😁 It worked!

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