Oboi here we go 🙄
Ubuntu has managed to do away with GNU Core Utilities in its default stack. The last three holdouts, cp, mv and rm, have moved to uutils’ coreutils; the Rust reimplementation Canonical has been feeding into the distro since 2025.
They had been held back from 26.04 LTS over flaws in the uutils versions. Everything else, from ls and cat to chmod and du, made that jump in earlier releases.
This change, while big, sits hidden away in an obscure mention in Canonical’s work-in-progress release notes for Ubuntu 26.10.
It’s been a long road
Canonical started oxidising Ubuntu last year, and Ubuntu 25.10 became the first release to ship coreutils as the default. That release also made sudo-rs the default privilege tool, replacing a command that had been in place for decades.
26.04 was the release where the plan did slow down quite a bit, as Canonical kept cp, mv, and rm on their GNU versions due to a bunch of TOCTOU issues that were blocking the full implementation.
These were caught during an audit, when Canonical commissioned Zellic for two rounds between December 2025 and March 2026, focusing on the most security-sensitive utilities first.
Across both rounds, Zellic raised 113 issues, and 44 of them were assigned CVEs. Canonical says the vast majority have been resolved.
Getting here has had its ups and downs, and the last stretch was not clean. In July, uutils cp went back into the archive and came straight out again after it broke live image builds.
The fix was quick; as the developers marked it “Critical,” the fix went upstream, and the migration landed in time for 26.10. What changes for you?
When typing commands, nothing changes for you on the surface. uutils coreutils is designed to be a drop-in replacement for essential GNU tools, and the project treats any divergence from GNU as a bug, further pointing out that some options may still be missing or behave differently.
So if you prefer staying on the GNU version, you have the option to install the coreutils-from-gnu package that houses all the required components.
The next stage
Coreutils is one piece of a broader campaign. Earlier this year, Canonical became a Gold Sponsor of the Trifecta Tech Foundation, pitching in €40,000 a year to fund memory-safe system software.
Under this, their current target is ntpd-rs, a Rust rewrite of the tools Ubuntu uses to keep its clock in sync. While work is still ongoing, it has already arrived for testing.
Its transition to being default is targeted for Ubuntu 27.04.
What Canonical is gradually building up towards is the completion of their oxidation vision for Ubuntu, and it’s not about blindly including new components. Rather, it looks like a measured approach that’s being worked out a few steps at a time.
Yea know that is a fair point. I guess I struggle to see any other reason to support this? Even though I believe rust is nominally more secure it’ll be a decade before any core utils clone will be as hardened as the original just by virtue of the original having decades of bug finding and fixes done already.
I don’t think canonical would go through the effort under normal circumstances but I think they’re just taking the opportunity in front of them to ride the rust hype into a less copyleft ecosystem.
This actually ties into a broader complaint I have that the rust ecosystem is built around MIT due to influence of the corporate backers of the rust foundation. Which is unfortunate because I actually really love rust as a language.
My bet is, Canonical as a service provider has a customer that is willing to pay for access to more secure rust utils. Or they want to save resources fixing CVEs.
There’s also the spectre of future security regulations possibly demanding these changes one day too.
I still think its built on someone else’s money. lol
Ubuntu did invest in a security audit of uutils. It revealed issues that show fundamental misunderstandings on how to use posix APIs. If they cared about security they would have postponed the adoption at least one more cycle. Uutils are they not ready for general availability.
Plus after decades of bug fixing coreutils doesn’t have lots of security issues.
The VP of engineering of canonical keynoted Rust conf about uutils and is pushing forward the project. My guess is for political capital inside canonical.
Will long term uutils or another coreutils written in Rust will be a great improvement. Today is not the day.
As an example look at that https://github.com/uutils/coreutils/issues/10011
Even calling it a race is a looking at the issue wrong. They are creating the file with more permissions that necessary and restricting later instead of the other way around.
There was another issue with chroot that had the same fundamental mistake.
But they created the file with too many permissions in a memory safe way.
This is so important!
Hmm you could very well be right. I guess I’m being to reasonable by knowing new rust code is not automatically (and not usually) more secure then old c battle tested c code. Shareholders and CEOs don’t understand that, I wouldn’t be surprised if someone’s been convinced rust is axiomatically more secure and bankrolling the migration over it
The otherside is just because code is old doesn’t mean its battle tested and doesn’t have bugs.
I think that aligns with the deployment strategy right? They are targeting 27 which is the middle release and not LTS. Get some mileage on it prior to 28 LTS.
But yeah, its all corpo speech when they talk about it. Its probably some executive decision of the likes of “We think Rust is axiomatically better, so let’s implement it” like you said.