Firefox Community Forum

Last few days I've been getting this popup:

Attention!!! Click to turn on the antivirus

or

Attention!!! Click to scan the device

obviously some phishing or something. How can I get rid of it?

I can't delete the malware "Startfenster. I tried to find help with "Google"-Search. Without any success! This malware exists for me in "Firefox" only. Other browsers are not affected. Perhaps anyone can help me... Thank's!

Despite pop ups being barred on my system I get the attached several times a day. Does anyone recognise it and how can I stop it? I have no Firefox extensions, and have run Norton without finding any problems. There is no indication of its source. It has been on my system for more than a month. Thank you Colin O'Brien

Does Firefox "remember" any browser data from another Windows user account? I created a guest account for someone today and while I was browsing, I got redirected to a site called fy3 dot fit which had the fake captcha. I did not open the run box and did not paste any commands from it, so is the guest account compromised or do I need to nuke Windows and start again? I read on reddit that it's an infostealer but if Firefox does not remember the other user account's browser data, does that mean nothing would be stolen if I did run it?

To sign into Chatgbt I used my google account. Mozilla asks me "do I want to store info in persistent storage?" I click "learn more" about persistent storage. It takes me to a page that has zero mention of the words "persistent storage". That is a huge UX error. It says to me that really, you don't want me to know about persistent storage, and prefer that I remain confused and feel forced to agree to things I may not really want to, because you're making it difficult to understand what's actually involved. Not cool. Definitely now considering changing my browser after over 20 years.

seems that after Firefox 150.0.3 (20260511200624). I cant access locally deployed servers that are not secure. the Firefox forces https when hitting http://localhost. I've tried to disable the HTTPS setting altogether. Even in developer mode it still overwrites http to https.

I am just burned out with Firefox and not sure why I should continue to use it instead of some fork or Chromium-based browser.

It seems like every update brings some new GenAI/LLM component that is auto-enabled and difficult to disable. I do not want GenAI/LLMs in my web browser. I have dropped nearly every other application or software that has forced it on me and included it in their product. I feel like I'm trying manage a Windows system having to follow blogs to debloat, restore privacy, and restore security. GenAI/LLMs shouldn't be in my web browser. And, they should be opt-in, not opt-out in some confusing mix of GUI and about:config madness. If GenAI/LLM is so great, then make it an extension or a fork then let those folks use it from there. Don't bake it into the web browser.

I continue to use Firefox for uBlock Origin but I guess that would be possible with a Firefox-fork. However, I am just tired of having to continuously manage my Firefox browser and battle websites that only support Chromium-based browsers. If Firefox actually seemed intent on improving security and privacy then I could find the motivation but this GenAI/LLM nonsense seems the point of no return.

On my Android phone, I've switched to a Chromium-based browser given the poor state of security and hardening for the vanilla Firefox. I keep IronFox on hand but it is just easier to surf the web with a Chromium-based browser due to many websites just working better. Why should I deal with the pain and frustration of limited Firefox support when Firefox isn't even keeping up with security hardening?

As for desktop, the Firefox browser just doesn't seem as snappy or stable as I would expect. Firefox for Linux is still not supported for Slack Huddles. How is it 2026 and Mozilla/Firefox are still not fully functional with one of the major business chat platforms? Yes, I know this primarily a Slack and AWS-Chime-SDK problem but it is also a Firefox problem because there isn't much that a user can do. I've tried to prod Slack and the AWS teams numerous times to support Firefox but they've just done nothing. I also see nothing being done by the Firefox team, too.

Another example is the EdgeSuite CDN. Nearly always they block my traffic when I use Firefox. Switch to a Chromium-based browser and EdgeSuite is much less likely to block me. This is fairly consistent for the retail and financial institutions I use.

As far as I am aware, many of the security concerns brought up by Madaidan in 2022 still hold true for Firefox today, especially for Android and Linux. If this is no longer true, then it might be good for the Firefox team to post a rebuttal or update clarifying the current state of Firefox. The average users such as myself only see the Madaidan blog post and have to take it at face value. https://madaidans-insecurities.github.io/firefox-chromium.html

Anyway, I don't see a way ahead for me and Firefox but maybe you can convince me. It just seems like Firefox and Mozilla have lost their way. They no longer seem focused on security and privacy. Instead they're forcing privacy, security, and system resource disasters onto their userbases, just like Microsoft, Google, and every one of the major tech firms. I just don't see why I should use, promote, and even support Firefox going into 2026.

When I open Firefox I get a large number of warnings. I have run three separate scans (Norton, Malwarebytes, Spybot S&D. I have then restarted my PC and these messages re-appear.

The essages state "Warning: Virus detected" "System Alert!" "Trojan Detected!

The messages try to lead me to watrixa.co.in to Scan & fix or remove the viruses. It will not let me close these warnings.

Hi, I am using Firefox exclusively for my work Claude account, I only check my usage on it. Today, I noticed Firefox silently installed a webapp under $USER/AppData/Roaming/Microsoft/Windows/Start Menu/Programs, and it has a Claude webapp, which I neither click any install or add to my menu. I found it extremely concerning in terms of privacy, and I am wondering if any other people have similar experience.

woke up after doozing watching a yt video and on my pc i couldn't oppen firefox and it kept crashing so i just booted my pc again

After that i could open firefox but it had a yellow simbol on the three dot setting sections that stated "new tab has downloaded a new component"

i searched online and they said it could be an hijacker i refreshed firefox and run an anlysis with the base windows antivirus

the antivirus say's i'm clean but i still kinda unsure:

  was it really an infection? i ask myself if it could be just a firefox bug i checked extention before refreshing and the only one was 7tv and nothing else

  if it was an hijacker how can i fully know if i'm clean? what better steps can i take?

I was prompted to install a .js file while on a website unrelated to mozilla organization. I was taking a work call and distracted at the time and was dumb enough to install it before I realized this was not a normal update. Should I uninstall and reinstall firefox? My McAfee blocked the script from "trying to hijack one of [my] apps"

Some extensions I use have been updated and now ask permission to "Access your data for all websites." What is the scope of this access? Can an extension which facilitates video downloads see my bank password? Can it access data for sites in a different Firefox container? Can it access sites which I use in a different browser? Can it access data for sites which, on my system, are only available to a different user? Thanks for any clarification. [I am running Firefox 149.0 under Kubuntu 24.04]

At the top of my settings it says: Information: Your browser is being managed by your organization.

What does this mean? It's my personal laptop, I bought it myself and I don't work for any organization.

Thanks for your help. Nancy

Pop ups appear when I start firefox saying "Trojan virus detected!" and "system alert!" including "remove virus now" button that if pressed takes me to a site which invites me to download what I assume is malware.

I accidentally clicked on a site that was supposed to be a game review site that I found on a Bing search. Now I get pop up ads for fake virus programs whenever I run Firefox.

I ran a scan with Mallware Bytes and Microsoft Defender and both scans came up clean.

I am including a screenshot of the popups.

Any ideas?

Thanks

I assume Mozilla developers are working on this?

https://singularityhub.com/2026/04/10/anthropics-mythos-ai-uncovered-serious-security-holes-in-every-major-os-and-browser/

Quote from the article

"Its capabilities are a step change from the previous best models. Given the challenge of attacking the Firefox web browser’s JavaScript engine, Anthropic’s previous most powerful model Opus 4.6 succeeded just twice, compared to 181 times for Mythos. Most worryingly, the team found that engineers with no security background could use it to develop successful attacks overnight."

Hi, When connecting to a HTTP:// site, when you enter your username in the username field, Firefox prompts the user with: "This connection is not secure. Logins entered here could be compromised. Learn More".

How can I turn this message off?

We are running Firefox in kiosk mode in the browser (on a Windows 11 PC), and they are logging into an HTTP site using a touch screen, but when they click into the username box, they sometimes miss touch where to enter this username and instead touch the link mentioned in the message. This then takes them to the Mozilla homepage, but because it is running in kiosk mode, they are unable to navigate back, and they are prevented from closing and restarting Firefox. This is why we need to turn the message off.

Hello! Long time Firefox user here, grew up with a father working in IT security. He's mentioned this a few times before, but now we've both really noticed the push towards using generative AI in roles in IT where it's really unsuitable, and honestly quite a risk to security and privacy, not to mention quite a waste of time having to fact check things properly because I cannot even be sure that the first result in a Google search for "how far away is the moon" will be correct. We're quite concerned that Firefox is following suit, especially with the new CEO evidently not understanding some of the fundamentals of why this browser has such a dedicated user base. Just wondering if saving the money by not having to hire competent, trained professionals who can provide the human touch needed to run a browser is truly worth eroding Firefox's reputation of being the genuinely good alternative to Chrome? How long before the AI stops being optional? How much of the code is going to end up written by some language learning algorithm and passed off as safe? If this push is to continue, what alternatives does anyone in the community suggest? Thank you for any responses from both myself and my father :-)