The Update Conundrum
the.unknown-universe.co.uk
How a “kept back” Proxmox kernel left my home lab exposed to CVE‑2026‑31431 — why I now check upgradable packages and use apt full‑upgrade.

cross-posted from: https://lemmy.ml/post/46701277

I’ve been running my home lab since 2021 and honestly thought my update routine was solid: apt update && apt upgrade, reboot, job done.

Turns out I was wrong. I was checking CVE‑2026‑31431 (Copy Fail) this morning and realised that despite my “successful” updates, I was still running a vulnerable kernel from March.

I’ve had to rethink how I handle host updates. If you’re relying on a standard upgrade and a reboot to keep Proxmox or Debian hosts safe, you might want to check if yours is lying to you as well.

  • DigDoug@lemmy.worldEnglish
    2·
    3 days ago

    Is this just a Proxmox thing? I’m running Debian on my server, and as far as I know, the kernel has always upgraded properly when there’s a new one available.

  • nomad@infosec.pubEnglish
    2·
    5 days ago

    You only need the reboot if a package update masks the retirement.

    The system is not lying to you, it holds some critical updates back to be installed separately and manually.

    The output shows you which packages have been held back. Just do apt-get install linux-image-amd64 for example, reboot and apt autoremove to remove the old kernel.

  • GreenKnight23@lemmy.worldEnglish
    2·
    5 days ago

    from my own experience, apt dist-upgrade removes old kernels, apt upgrade still installed the new kernel, grub updated and booted into the new kernel.

    all dist-upgrade did (for me) was delete the old kernels. which is something I would prefer not to do because it removes any ability to rollback should I absolutely need to.

  • Suzune@ani.socialEnglish
    51·
    8 days ago

    I’ve seen that the patches are only available in the debian-security repository. It’s important to review your repo list in /etc/apt/sources.list.d.

  • KairuByte@lemmy.dbzer0.comEnglish
    3·
    7 days ago

    I mean, you could just use the proxmox UI for updates. Single point for all servers, just click in and hit update. It explicitly runs dist-upgrade already.

  • BCsven@lemmy.caEnglish
    2·
    7 days ago

    The nice thing about zypper is the various patch options and reporting. Gives you a good picture of what CVEs, rating, and if installed, needed, not needed etc. Does Apt have something similar?