s390/vfio-ap: Fix hot-unplug skipped when last AP adapter or domain removed

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89957
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:17:06 UTC
Updated2026-09-16 15:18:20 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 f58e824de8577fe411f6199d659731a0f86a7275 git Not specified
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 3a9b049bbdc40165d7f3e20b818eec95e5694d96 git Not specified
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 753aa3bb1273bc0d36adb013d5915cc8ff6b72a9 git Not specified
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 c45753c32d452d10d8efaeb52587e9e6e8126e33 git Not specified
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 04b35dd88c108b2d2ceaaa396aba1cb4049d5831 git Not specified
CNA Linux Linux affected eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 917f509bfb88048094dbb85c4e9dbc4d6fe4a886 git Not specified
CNA Linux Linux affected 6.0 Not specified
CNA Linux Linux unaffected 6.0 semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/917f509bfb88048094dbb85c4e9dbc4d6fe4a886 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3a9b049bbdc40165d7f3e20b818eec95e5694d96 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f58e824de8577fe411f6199d659731a0f86a7275 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/04b35dd88c108b2d2ceaaa396aba1cb4049d5831 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c45753c32d452d10d8efaeb52587e9e6e8126e33 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/753aa3bb1273bc0d36adb013d5915cc8ff6b72a9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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