Mozilla has published release notes for Firefox browser version 151.0, and this update includes several genuinely meaningful privacy and security improvements.

Three changes stand out in particular:

• Stronger anti‑fingerprinting
• Broader protection for local network access
• More control over private sessions and permissions

Note that Mozilla says several Firefox 151 features are “part of a progressive roll out,” meaning they will appear for some users first and be expanded over time. So, you may not see all of them immediately.

Privacy

One of the more visible additions is a new “end private session” control in Private Browsing Mode. Instead of closing every private window to clear your traces, you now get a dedicated fire‑icon button next to the address bar that wipes the current private session’s data and immediately starts a fresh one.

Under the hood, this clears the usual private browsing artifacts for that session, including history, cookies, cached files, and other site data that would normally disappear only when the last private window closes.

For people who routinely mix normal and private windows, this is safer and less error‑prone than hunting down every private tab before you walk away from the machine.

Firefox 151 also tightens its defenses against browser fingerprinting in the default “Standard” Enhanced Tracking Protection (ETP) mode. Mozilla says Firefox now limits the amount of device and browser information exposed to websites in a way that reduces the number of uniquely identifiable users by about 14% overall, and by roughly 49% on macOS.

This makes it harder for trackers to pick you out of the crowd, especially on platforms with fewer users to begin with (like certain macOS configurations). This reduces the privacy risk surface by default, which makes it harder for phishing and landing pages that redirect visitors to “categorize” you.

Another important change is Firefox’s “local network access restrictions,” which are now rolling out to all users, not just those who turned Enhanced Tracking Protection to Strict.

This means that when a website wants to communicate with devices on your local network, or with apps and services running on your machine, Firefox now asks for permission first. Chrome and Edge have been rolling out similar permission prompts.

Security

Firefox 151 also quietly fixes several security vulnerabilities.

The most notable example is CVE‑2026‑8953, a sandbox escape due to a use‑after‑free in the Disability Access APIs component. While there are currently no reports of in‑the‑wild exploitation for this specific bug at the time of writing, this is the kind of bug cybercriminals love.

A use-after-free (UAF) is a software memory vulnerability where a program attempts to access a memory location after it has been freed. If the program fails to clear the pointer to that freed memory, attackers can manipulate the error to crash the system or execute arbitrary code. A memory corruption leading to a sandbox escape is exactly the kind of link attackers want to complete a browser exploit chain.

How to update

If you’re running Firefox in a home or small‑office environment, we recommend updating to Firefox 151 as soon as possible to get the fingerprinting protections, local network access prompts, and security patches.

To update Firefox:

• Open Firefox
• Click the menu (three stacked lines) in the upper-right corner
• Go to Help > About Firefox
• Firefox will automatically check for updates and begin downloading them
• Restart the browser when prompted to complete the update

Once your Firefox browser has been updated, it will show a green checkmark along with the message: “Firefox is up to date.”

---

Let’s face it, an incognito window can only do so much. 
 
Breaches, dark web trading, credit fraud. Malwarebytes Identity Theft Protection monitors for all of it, alerts you fast, and comes with identity theft insurance. 

Some software providers have decided to lead by example and offer users a choice about the Artificial Intelligence (AI) features built into their products.

The latest example is Mozilla, which now offers users a one-click option to disable generative AI features in the Firefox browser.

Audiences are divided about the use of AI, or as Mozilla put it on their blog:

“AI is changing the web, and people want very different things from it. We’ve heard from many who want nothing to do with AI. We’ve also heard from others who want AI tools that are genuinely useful. Listening to our community, alongside our ongoing commitment to offer choice, led us to build AI controls.”

Mozilla is adding an AI Controls area to Firefox settings that centralizes the management of all generative AI features. This consists mainly of a master switch, “Block AI enhancements,” which lets users effectively run Firefox “without AI.” It blocks existing and future generative AI features and hides pop‑ups or prompts advertising them.

Once you set your AI preferences in Firefox, they stay in place across updates. You can also change them whenever you want.

Starting with Firefox 148, which rolls out on February 24, you’ll find a new AI controls section within the desktop browser settings.

You can turn everything off with one click or take a more granular approach. At launch, these features can be controlled individually:

• Translations, which help you browse the web in your preferred language.
• Alt text in PDFs, which add accessibility descriptions to images in PDF pages.
• AI-enhanced tab grouping, which suggests related tabs and group names.
• Link previews, which show key points before you open a link.
• An AI chatbot in the sidebar, which lets you use your chosen chatbot as you browse, including options like Anthropic Claude, ChatGPT, Microsoft Copilot, Google Gemini and Le Chat Mistral.

We applaud this move to give more control to the users. Other companies have done the same, including Mozilla’s competitor DuckDuckGo, which made AI optional after putting the decision to a user vote. Earlier, browser developer Vivaldi took a stand against incorporating AI altogether.

Open-source email service Tuta also decided not to integrate AI features. After only 3% of Tuta users requested them, Tuta removed an AI copilot from its development roadmap.

Even Microsoft seems to have recoiled from pushing AI to everyone, although so far it has focused on walking back defaults and tightening per‑feature controls rather than offering a single, global off switch.

Choices

Many people are happy to use AI features, and as long as you’re aware of the risks and the pitfalls, that’s fine. But pushing these features on users who don’t want them is likely to backfire on software publishers.

Which is only right. After all, you’re paying the bill, so you should have a choice. Before installing a new browser, inform yourself not only about its privacy policy, but also about what control you’ll have over AI features.

Looking at recent voting results, I think it’s safe to say that in the AI gold rush, the real premium feature isn’t a chatbot button—it’s the off switch.

---

We don’t just report on privacy—we offer you the option to use it.

Privacy risks should never spread beyond a headline. Keep your online privacy yours by using Malwarebytes Privacy VPN.