Vue lecture
Pop!_OS 24.04 LTS released
Version 24.04 LTS of the Ubuntu-based Pop!_OS distribution has been released with the COSMIC Desktop Environment:
Today is special not only in that it's the culmination of over three years of work, but even more so in that System76 has built a complete desktop environment for the open source community. We're proud of this contribution to the open source ecosystem. COSMIC is built on the ethos that the best open source projects enable people to not only use them, but to build with them. COSMIC is modular and composable. It's the flagship experience for Pop!_OS in its own way, and can be adapted by anyone that wants to build their own unique user experience for Linux.
In addition to the COSMIC desktop environment, Pop!_OS is now available for Arm computers with the 24.04 LTS release, and the distribution has added hybrid graphics support for better battery life. LWN covered an alpha version of COSMIC in August 2024.
Rust 1.92.0 released
Version 1.92.0 of Rust has been released. This release includes a number of stabilized APIs, emits unwind tables by default on Linux, validates input to #[macro_export], and much more. See the separate release notes for Rust, Cargo, and Clippy.
[$] Toward a policy for machine-learning tools in kernel development
Security updates for Thursday
[$] LWN.net Weekly Edition for December 11, 2025
- Front: Rust in CPython; Python frozendict; Bazzite; IETF post-quantum disagreement; Distrobox; 6.19 merge window; Leaving the TAB.
- Briefs: Let's Encrypt retrospective; PKI infrastructure; Rust in kernel to stay; CNA series; Alpine 3.23.0; cmocka 2.0; Firefox 146; 2024 Free Software Awards; Quotes; ...
- Announcements: Newsletters, conferences, security updates, patches, and more.
10 Years of Let's Encrypt Certificates
Let's Encrypt has published a retrospective that covers the decade since it published its first publicly trusted certificate in September 2015:
In March 2016, we issued our one millionth certificate. Just two years later, in September 2018, we were issuing a million certificates every day. In 2020 we reached a billion total certificates issued and as of late 2025 we're frequently issuing ten million certificates per day. We're now on track to reach a billion active sites, probably sometime in the coming year.
Kroah-Hartman: Linux CVEs, more than you ever wanted to know
Greg Kroah-Hartman is writing a series of blog posts about Linux becoming a Certificate Numbering Authority (CNA):
It's been almost 2 full years since Linux became a CNA (Certificate Numbering Authority) which meant that we (i.e. the kernel.org community) are now responsible for issuing all CVEs for the Linux kernel. During this time, we've become one of the largest creators of CVEs by quantity, going from nothing to number 3 in 2024 to number 1 in 2025. Naturally, this has caused some questions about how we are both doing all of this work, and how people can keep track of it.
So far, Kroah-Hartman has published the introductory post, as well as a detailed post about kernel version numbers that is well worth reading.
[$] Mix and match Linux distributions with Distrobox
Linux containers have made it reasonably easy to develop, distribute, and deploy server applications along with all the distribution dependencies that they need. For example, anyone can deploy and run a Debian-based PostgreSQL container on a Fedora Linux host. Distrobox is a project that is designed to bring the cross-distribution compatibility to the desktop and allow users to mix-and-match Linux distributions without fussing with dual-booting, virtual machines, or multiple computers. It is an ideal way to install additional software on image-based systems, such as Fedora's Atomic Desktops or Bazzite, and also provides a convenient way to move a development environment or favorite applications to a new system.
Security updates for Wednesday
The (successful) end of the kernel Rust experiment
(Stay tuned for details in our Maintainers Summit coverage.)
The 2024 Free Software Awards winners
[$] Bazzite: a gem for Linux gamers
One of the things that has historically stood between Linux and the fabled "year of the Linux desktop" is its lack of support for video games. Many users who would have happily abandoned Windows have, reluctantly, stayed for the video games or had to deal with dual booting. In the past few years, though, Linux support for games—including those that only have Windows versions—has improved dramatically, if one is willing to put the pieces together. Bazzite, an image-based Fedora derivative, is a project that aims to let users play games and use the Linux desktop with almost no assembly required.
Firefox 146 released
Version
146.0 of the Firefox web browser has been released. One feature of
particular interest to Linux users is that Firefox now natively
supports fractional scaled displays on Wayland. Firefox Labs has also
been made available to all users even if they opt out of telemetry or
participating in studies. "This means more experimental features
are now available to more people.
"
This release also adds support for Module-Lattice-Based
Key-Encapsulation Mechanism (ML-KEM) for WebRTC. ML-KEM is
"believed to be secure against attackers with large quantum
computers
". See the release notes for all changes.
Security updates for Tuesday
[$] Disagreements over post-quantum encryption for TLS
The Internet Engineering Task Force (IETF) is the standards body responsible for the TLS encryption standard — which your browser is using right now to allow you to read LWN.net. As part of its work to keep TLS secure, the IETF has been entertaining proposals to adopt "post-quantum" cryptography (that is, cryptography that is not known to be easily broken by a quantum computer) for TLS version 1.3. Discussion of the proposal has exposed a large disagreement between participants who worried about weakened security and others who worried about weakened marketability.
Addressing Linux's missing PKI infrastructure
Jon Seager, VP of engineering for Canonical, has announced a plan to develop a universal Public Key Infrastructure tool called upki:
Earlier this year, LWN featured an excellent article titled "Linux's missing CRL infrastructure". The article highlighted a number of key issues surrounding traditional Public Key Infrastructure (PKI), but critically noted how even the available measures are effectively ignored by the majority of system-level software on Linux.
One of the motivators for the discussion is that the Online Certificate Status Protocol (OCSP) will cease to be supported by Let's Encrypt. The remaining alternative is to use Certificate Revocation Lists (CRLs), yet there is little or no support for managing (or even querying) these lists in most Linux system utilities.
To solve this, I'm happy to share that in partnership with rustls maintainers Dirkjan Ochtman and Joe Birr-Pixton, we're starting the development of upki: a universal PKI tool. This project initially aims to close the revocation gap through the combination of a new system utility and eventual library support for common TLS/SSL libraries such as OpenSSL, GnuTLS and rustls.
No code is available as of yet, but the announcement indicates that upki will be available as an opt-in preview for Ubuntu 26.04 LTS. Thanks to Dirjan Ochtman for the tip.