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ZDNET's key takeaways

• The Linux desktop will continue to grow.
• Linux and open-source security will both improve.
• Firefox is in deep, deep trouble.

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Clearly, AI will play a larger role in Linux and open source next year, but that's true of pretty much all technology. However, while AI will be used to help develop the Linux kernel, no one is predicting, a la Windows, that AI will be used to rewrite the entire codebase by 2030. That said, open source will remain at the heart of AI.

The continued rise of the Linux desktop

For Linux, I see more desktop distributions aimed at ex-Windows users. As a result, the Linux desktop, which has already been growing faster than ever, will continue to grow even faster. Microsoft is helping by continuing to push AI down Windows users' throats. Attention Satya Nadella, Microsoft's CEO: Windows fans don't want AI. Sure, some do. Most, however, don't.

Also: My 11 favorite Linux distributions of all time, ranked

In addition, as my colleague on the Windows side of life, Ed Bott, points out, Microsoft's current course toward more restrictions on which applications Windows can run, and a monthly subscription model for Windows, is almost certain to disillusion even hardcore Windows users.

All this means Linux's opportunity for growth will only continue to grow. Now, we'll see if Linux can take advantage of its new chances. You see, as Linus Torvalds himself pointed out long ago, we have too many Linux desktops.

Imagine yourself at a grocery store in another country, and you want a new breakfast cereal. You're presented with over a hundred different boxes, and you don't know a thing about any of them. How will you decide? Or will you just throw up your hands and order Windows 12 via Amazon from back home because you can't make heads or tails of all the local cereals?

It's the same with Linux. If you go to DistroWatch, you'll find over a hundred desktops. I can't tell them all apart, and I cover this stuff for a living. We need a distro to step forward to become the top choice.

That has never happened because every Linux distribution maker thinks their way is the best way. The closer you look, the more differences you'll find between the distros. For example, there are more than half a dozen viable Linux desktop interfaces such as KDE Plasma, GNOME, Cinnamon, etc.

I have some ideas on how to address this issue, but that's a story for another day. For now, even though there are still too many Linux desktops, the Linux desktop will continue to grow.

Rust becomes 'normal' in kernel and core tools

Earlier this month, Linux kernel developers formally ended the "Rust experiment," declaring Rust a permanent core language for Linux. Indeed, the Direct Rendering Manager (DRM) graphics maintainers are already talking about requiring Rust for new drivers within about a year.

Even before, the Debian Linux developers had decided that, by May 2026, all further development of its core APT package manager would be done in Rust. Why? Because Rust is memory safe. This stops in their tracks many kinds of security problems that C, Linux's main language, has proven all too prone to over the decades.

Don't think, however, that it's all peaches and cream now for Rust on Linux. 

Also: Rust turns 10: How a broken elevator changed software forever

As Miguel Ojeda, leader of the Rust for Linux project, has said, "Rust is here to stay, ... this does not mean that everything works for every kernel configuration, architecture, toolchain, etc." 

There's still a lot of work to be done. That said, Ojeda also noted that Android 16 devices based on the 6.12 Linux kernel include the new Rust-based anonymous shared memory allocator (ashmem). That means millions of devices are already using Rust for Linux in production. Rust is here. Rust is real. And Rust is already at work.

However, unlike Microsoft, which appears to plan to move all of Windows to Rust by 2030, there are no such plans for Linux. Someday, all of Linux may be written in Rust, but I can't see it happening until the 2050s, and maybe not even then. After all, for pure performance, short of writing code in assembler, nothing's faster than C.

Oh, and for Windows' Rust plans? Good luck with converting that mess of a codebase into Rust in four years. Fourteen? Maybe.

Immutable Linux goes mainstream

Immutable Linux distributions are gaining traction because read-only system images, atomic updates, and transactional package layers significantly simplify rollback and reduce "dependency hell." Analysts are explicitly framing immutability as a "new era of security and stability."

Also: 5 reasons to switch to an immutable Linux distro today - and which to try first

Now, immutable Linux distros, such as Fedora Silverblue, OpenSUSE MicroOS, and Ubuntu Core, have been around for a while. Previously, though, only Linux enthusiasts used them in containers. Enterprise Linux is now switching to them.

The leading example of an immutable business is the new Red Hat Enterprise Linux (RHEL) 10. While you can still use the old tools to maintain RHEL, you now have the choice of going the immutable route. As time goes on, I expect more enterprise distributions to follow this trend. It's much easier to manage.

Security and supply-chain hardening across the stack

Some inherent changes, such as Rust's integration into Linux, are guaranteed to make Linux more secure. 

Linux and open source are also on track to become more secure in 2026, as the ecosystem simultaneously hardens the kernel, professionalizes supply-chain defenses, and scales coordinated security programs like the Open Source Security Foundation (OpenSSF) across vendors and governments.

Starting with Linux, the Kernel Self-Protection Project and similar efforts are pushing more exploit-mitigation features upstream. Simultaneously, risk-based patching and AI-assisted triage are making it easier to prioritize and deploy fixes at scale.

Also: Immutable Linux delivers serious security - here are your 5 best options

At the same time, open-source supply-chain attacks have driven widespread adoption of Software Bill of Materials (SBOMs), Supply Chain Levels for Software Artifacts (SLSA), and signed provenance. 

Sigstore is now integrated into major platforms like GitHub and GitLab, which will make verifiable signing routine by 2026. That's important because, more than ever, developers need to know what's actually in any given program and who really wrote it.

It's not just, by the way, that this just makes good security sense. In Europe, with the EU Cyber Resilience Act (CRA) now in force, it's the law. The CRA requires anyone, by the end of next year, who sells any product containing software, including open-source programs, to have an SBOM. Period. End of statement.

Open source becomes essential for AI agents

Last year, over in AI land, everyone was talking about how 2025 would be the year of Agentic AI. Leading the hype pack was OpenAI founder Sam Altman, who said, "In 2025, we may see the first AI agents join the workforce and materially change the output of companies." He was wrong. Agents aren't ready yet.

Also: Why AI agents failed to take over in 2025 - it's 'a story as old as time,' says Deloitte

If AI agents are really going to be all that -- and I'm not convinced they will be -- it will be because of the open-standard Agentic AI Foundation (AAIF). This new, open standards industry-backed consortium gets pretty much everyone who's anyone in AI agents on the same page for sharing data and making interactions easy for agents. Without interoperability, agents will go nowhere.

Firefox falls

I started this story by mentioning how people are annoyed with Microsoft for forcing AI on its users. Their bad temper is nothing -- nothing -- compared to how Firefox users are reacting to Mozilla pushing AI into their favorite browser.

When Mozilla declared that AI would be Firefox's future, its users quickly said, and I quote from the Mozilla Connect list, "Once again, Mozilla is SPRINTING to chase after the stupidest tech-brained trends and not actually focused on improving the product at all." 

This was followed up by comments such as "Stop chasing slop and actually work on making sure your browser competes with Chromium in REAL areas like speed and functionality, not in digital hallucinations." And one I especially liked: "I would LOVE a function that helps me remove AI slop from my everyday browser. I would really encourage Mozilla to develop this."

Mozilla backed off quickly. 

Also: Why I'm deleting Firefox for good - and which browser's never let me down

On Mastodon, Mozilla retreated to "Firefox will have an option to completely disable all AI features. We've been calling it the AI kill switch internally. I'm sure it'll ship with a less murderous name, but that's how seriously and absolutely we're taking this."

I think the damage has already been done. As I've been saying for years, Firefox has been declining. 

The people in charge of the project keep chasing one new tech craze after another, such as briefly accepting cryptocurrency donations and Firefox Hello, a built-in WebRTC video and voice calling feature, while abandoning popular features such as built-in RSS support (Live Bookmarks) and legacy add-ons/XUL extensions. 

Mozilla has also pursued such massive projects as its own device operating system, Firefox OS; a Virtual Private Network (VPN); and Mozilla Monitor Plus, a paid data-broker scan and removal service. What Mozilla hasn't been doing, many Firefox users have complained, is improving Firefox's performance.

Also: I've tried nearly every browser out there and these are my top 4 (spoiler: none are Chrome)

The result has been that Firefox's popularity has been sinking into irrelevance for years. Over the last 90 days, Firefox's market share has sunk in the US to a mere 1.7%. At one time, Firefox had a 34.1% market share. It will never see those numbers again. I fear, by this time next year, thanks to how annoyed its most loyal users are, it will drop below 1%.

Firefox was once one of open source's greatest success stories. Now, its day is almost done.

Well, it couldn't all be great days ahead, could it? Still, taken all in all-in-all, I expect 2026 to be a banner year for both Linux and open-source software.