CVE-2026-89957 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-DEBIAN12-LINUX612-20507218
- published5 Oct 2026
- disclosed16 Sept 2026
Introduced: 16 Sep 2026
NewCVE-2026-89957 (opens in a new tab)How to fix?
Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
s390/vfio-ap: Fix hot-unplug skipped when last AP adapter or domain removed
The vfio_ap_mdev_hot_unplug_cfg() function uses the return value of bitmap_andnot() to determine whether the guest APCB needs to be updated. However, bitmap_andnot() returns false when the resulting destination bitmap is empty. This means that if the only adapter, domain or control domain assigned to an mdev is removed from the host's AP configuration, the bit is correctly cleared from the shadow APCB, but bitmap_andnot() returns false because the result is an empty bitmap. Consequently, do_hotplug remains 0 and vfio_ap_mdev_update_guest_apcb() is never called, leaving the KVM guest with stale hardware access to the unplugged AP devices.
Fix this by replacing the bitmap_andnot() return value check with bitmap_intersects() to determine whether the shadow APCB actually overlaps with the removal mask. If there is an intersection, call bitmap_andnot() solely for its side effect of clearing the bits, then unconditionally set do_hotplug to trigger the guest APCB update.
References
- https://security-tracker.debian.org/tracker/CVE-2026-89957
- https://git.kernel.org/stable/c/04b35dd88c108b2d2ceaaa396aba1cb4049d5831
- https://git.kernel.org/stable/c/3a9b049bbdc40165d7f3e20b818eec95e5694d96
- https://git.kernel.org/stable/c/753aa3bb1273bc0d36adb013d5915cc8ff6b72a9
- https://git.kernel.org/stable/c/917f509bfb88048094dbb85c4e9dbc4d6fe4a886
- https://git.kernel.org/stable/c/c45753c32d452d10d8efaeb52587e9e6e8126e33
- https://git.kernel.org/stable/c/f58e824de8577fe411f6199d659731a0f86a7275