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Headlines for May 18, 2026
Kernel prepatch 7.1-rc4
The 7.1-rc4 kernel prepatch is out for testing.
Some of the documentation updates might be worth highlighting: the continued flood of AI reports has basically made the security list almost entirely unmanageable, with enormous duplication due to different people finding the same things with the same tools. People spend all their time just forwarding things to the right people or saying "that was already fixed a week/month ago" and pointing to the public discussion.Which is all entirely pointless churn, and we're making it clear that AI detected bugs are pretty much by definition not secret, and treating them on some private list is a waste of time for everybody involved - and only makes that duplication worse because the reporters can't even see each other's reports.
(He is referring to this pull request with patches from Willy Tarreau defining what constitutes a security bug and responsible ways to use AI to find bugs).
RIP Peter G. Neumann
We have received word that Peter G. Neumann, who, among many other things, ran the RISKS Digest for decades, has passed away. He will be much missed.
Update: the New York Times has published an obituary of Dr. Neuman.
Some weekend stable kernel updates
The 7.0.9, 6.18.32, 6.12.90, and 6.6.140 stable kernels have been released. Each contains yet another set of important fixes.
[$] Controlling memory management with BPF
Roman Gushchin began his session in the memory-management track of the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit by saying that the community has seen a lot of proposals adding BPF-based interfaces for memory management. None of them have made their way into the mainline, though. He wanted to explore the ways in which BPF might be helpful and the obstacles that have kept BPF-based solutions out so far. This session was followed by a discussion led by Shakeel Butt on what the requirements for a new, BPF-based interface for memory control groups might look like.
Seven new stable kernels with patches for CVE-2026-46333
Greg Kroah-Hartman has announced the 7.0.8, 6.18.31, 6.12.89, 6.6.139, 6.1.173, 5.15.207, and 5.10.256 stable kernels. These kernels contain a patch for CVE-2026-46333 a vulnerability reported by the Qualys Security Advisory team, though Jann Horn proposed a patch in 2020. The vulnerability has a proof-of-concept exploit published already. Some of the kernels have additional patches for other bugs; as always, users are advised to upgrade.
[$] HugeTLB preservation over live update
Recent times have seen a lot of effort put into the implementation of the kexec handover and live update orchestrator features in the Linux kernel. But that work is not yet complete. At the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit, Pratyush Yadav led a memory-management-track session on adding the ability to preserve hugetlbfs-provided memory during the live-update process.
Security updates for Friday
Security updates have been issued by Debian (ffmpeg, gsasl, nodejs, postgresql-15, postgresql-17, python3.9, and thunderbird), Fedora (expat, firefox, freerdp, GitPython, kernel, php, rust-podman-sequoia, rust-rpm-sequoia, rust-sequoia-chameleon-gnupg, rust-sequoia-git, rust-sequoia-keystore-server, rust-sequoia-octopus-librnp, rust-sequoia-openpgp, rust-sequoia-sop, rust-sequoia-sq, and rust-sequoia-sqv), Mageia (awstats, libreoffice, perl-HTTP-Tiny, and tomcat), Oracle (corosync, freerdp, gimp, git-lfs, glib2, jq, kernel, krb5, libsoup3, libtiff, openexr, thunderbird, uek-kernel, and yggdrasil), Red Hat (podman and skopeo), SUSE (amazon-ssm-agent, avahi, c-ares, cairo, containerd, cpp-httplib, dnsmasq, dovecot24, ffmpeg-4, firefox, helm, ImageMagick, iproute2, kernel, krb5, libtpms, ongres-scram, ongres-stringprep, plexus-testing, maven, maven-doxia, mojo-parent, sisu, openCryptoki, openssh, perl-Text-CSV_XS, php8, python-lxml, python-Twisted-doc, python311-click, python311-GitPython, rclone, regclient, and syncthing), and Ubuntu (avahi).
[$] Policy groups for memory management
The kernel's control-group subsystem works well for resource management, Chris Li said at the beginning of his memory-management-track session at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit. Control groups work less well for other use cases, though. He was there to present his proposed enhancement, called "policy groups", that would address some of the shortcomings that he has encountered. A consensus on how this feature should look still seems distant, though.
[$] Buffered atomic writes, writethrough, and more
In back-to-back sessions at the start of the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit (which spilled over into a third slot), the atomic-buffered-writes feature was discussed. In the first session, Pankaj Raghav and Andres Freund set the stage with an introduction to the problem, along with a use case for its solution: the PostgreSQL database system. In the second, Ojaswin Mujoo described a potential way forward for the feature using an approach based on writethrough, which effectively means that the kernel immediately writes the data to disk instead of waiting for writeback from the page cache to occur. As might be expected, there was quite a bit of discussion among the assembled filesystems and storage developers during the combined sessions for those tracks.
Three stable kernels for Thursday
Greg Kroah-Hartman has announced the release of the 7.0.7, 6.18.30, and 6.12.88 stable kernels. These kernels do not include a patch for the Fragnesia local-privilege-escalation exploit that came to light on May 13, but do include many other important fixes throughout the tree. Users are, as always, advised to upgrade.
[$] Keeping COWs in context (a.k.a. anonymous reverse mapping)
The kernel's reverse-mapping machinery is charged with locating the
page-table entries that refer to a given page in memory. The reverse
mapping of anonymous pages is handled differently than for file-backed
pages. The kernel's implementation of reverse mapping for anonymous pages
is, according to Lorenzo Stoakes in his proposal
for a memory-management-track session at the 2026 Linux Storage,
Filesystem, Memory Management, and BPF Summit, "a very broken
abstraction
", due to its complexity. It also has some performance
problems. Stoakes was there to present, in raw form, a proposed
replacement that he calls a "COW context".
Security updates for Thursday
Security updates have been issued by AlmaLinux (gimp, jq, and yggdrasil), Debian (nghttp2 and thunderbird), Fedora (chromium, firefox, freerdp, GitPython, kernel, kernel-headers, krb5, nano, nix, nodejs20, php, python-click, python-django5, SDL2_image, and xen), Mageia (dnsmasq, flatpak, kernel, kmod-virtualbox, kernel-linus, perl-Net-CIDR-Lite, perl-XML-LibXML, and redis), SUSE (dnsmasq, firefox, jupyter-jupyterlab, kernel, krb5, libvinylapi3, log4j, Mesa, mozjs60, NetworkManager, OpenImageIO, python-Mako, python-Pillow, and python39), and Ubuntu (dnsmasq and nginx).
[$] LWN.net Weekly Edition for May 14, 2026
Posted May 14, 2026 1:04 UTC (Thu)The LWN.net Weekly Edition for May 14, 2026 is available.
Inside this week's LWN.net Weekly Edition
- Front: Fedora AI; Forgejo "carrot" disclosure; memory-management maintainership; huge THPs; mshare; 64KB base pages; DAMON; direct map.
- Briefs: Dirty Frag; Fragnesia; Mythos and curl; killswitch; Debian reproducible builds; KDE investment; Quotes ...
- Announcements: Newsletters, conferences, security updates, patches, and more.
[$] Friction in Fedora over AI developer desktop initiative
A push by Red Hat employees to create a Fedora "AI Developer Desktop" with support for out-of-tree kernel drivers and AI toolkits has been met with objections from some long-time members of the Fedora community. After more than a month of sometimes heated discussion, the Fedora Council had voted to approve the initiative; however, a last-minute change to vote against the proposal by council member Justin Wheeler has (at least temporarily) sent it back to the drawing board.
Yet another Dirty Frag type vulnerability: Fragnesia
Sam James has sent an announcement to the OSS Security mailing list about another local-privilege-escalation (LPE) exploit in the same class as Dirty Frag, called "Fragnesia". From the disclosure:
This is a separate bug in the ESP/XFRM from dirtyfrag which has received its own patch. However, it is in the same surface and the mitigation is the same as for dirtyfrag.
It abuses a logic bug in the Linux XFRM ESP-in-TCP subsystem to achieve arbitrary byte writes into the kernel page cache of read-only files, without requiring any race condition.
James noted that there is a patch in the works, but it has not yet been pulled into Linus Torvalds's tree nor into any of the stable kernels. A proof of concept exploit is also available.
[$] Managing pages outside of the direct map
When Brendan Jackman proposed
a session for the 2026 Linux Storage,
Filesystem, Memory Management, and BPF Summit, his topic was "a
pagetable library for the kernel
". During the actual
memory-management-track session, though, he stated that the idea had
"fizzled
" and he was going to cover related topics instead. What
resulted was a session on ways to efficiently manage pages that are not
present in the kernel's direct map.
[$] Revisiting mshare
Linux can share memory between processes, but each process (almost always) has its own set of page tables. In situations where vast numbers of processes are sharing a memory region, the combined size of the page tables can exceed that of the shared memory itself. There has, thus, long been an interest in enabling unrelated processes to share page tables referring to shared memory. Anthony Yznaga is the latest developer to try to push this idea (known as "mshare") forward; he described the status of that work in a memory-management-track discussion at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF).
Security updates for Wednesday
Security updates have been issued by AlmaLinux (corosync, freerdp, git-lfs, glib2, jq, kernel-rt, krb5, libpng, libtiff, openexr, and thunderbird), Debian (exim4), Mageia (apache, perl-Gazelle, php, and sed), Slackware (expat), SUSE (assimp-devel, go1.26, libQt6Svg6, python-jupyterlab, raylib, thunderbird, tor, and trivy), and Ubuntu (exim4).
Sovereign Tech Fund invests in KDE
The KDE project has announced
that it has been awarded over €1 million from the Sovereign Tech Fund
to improve its desktop-environment software. "The investment will be
used to strengthen the structural reliability and security of KDE's core
infrastructure, including Plasma, KDE Linux, and the frameworks underlying
its communication services.
"
[$] Using dma-bufs for read and write operations
The kernel's dma-buf subsystem provides a way for drivers to share memory buffers, usually in order to support efficient device-to-device I/O. At the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit, Pavel Begunkov, assisted by Kanchan Joshi, led a joint session of the storage and memory-management tracks to explore ways to make the use of dma-bufs more efficient yet, and to make them available for read and write operations initiated by user space.