What is CVE-2026-89957?

CVE-2026-89957 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10, affecting Linux kernel versions from 6.0 onward and patched in 6.1.188, 6.6.157, 6.12.110 and others. CVE-2026-89957 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89957?

CVE-2026-89957 has a CVSS score of 8.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Is there a patch available for CVE-2026-89957?

Yes, CVE-2026-89957 has been patched. Fixed versions include 6.1.188, 6.6.157, 6.12.110 and others. If you are running Linux kernel 6.0 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89957 actively exploited?

CVE-2026-89957 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89957

High

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.

Package Linux Kernel

Published 2026-09-16

Last modified 2026-09-16

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

8.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.0 and later are affected. Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5, 7.3-rc1 and their respective stable series.

Affected from

≥ 6.0

Fixed in

✓ 6.1.188 6.1.x ✓ 6.6.157 6.6.x ✓ 6.12.110 6.12.x ✓ 6.18.51 6.18.x ✓ 7.2.5 7.2.x ✓ 7.3-rc1

References

6 total

Showing 5 of 6 references View all on NVD

Details

CVE ID CVE-2026-89957

Severity High

CVSS score 8.8 / 10

CVSS version 3.1

Published 2026-09-16

Modified 2026-09-16

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89957?

CVE-2026-89957 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10 . It affects Linux kernel versions from 6.0 onward and has been patched in 6.1.188, 6.6.157, 6.12.110 and others. CVE-2026-89957 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89957?

CVE-2026-89957 has a CVSS score of 8.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Is there a patch available for CVE-2026-89957?

Yes. CVE-2026-89957 has been patched. Fixed versions include 6.1.188, 6.6.157, 6.12.110 and others. If you are running Linux kernel 6.0 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89957 actively exploited?

No. CVE-2026-89957 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.