Skip to content
Fencer Vulns
no cvss —

CVE-2026-90097 json

Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition

published 2026-09-17 52 d ago modified 2026-10-30 9 d ago also EUVD-2026-81958

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition

The VMBus module initialization function, hv_acpi_init(), currently does nothing when running in the root partition and root is not nested in another VM. But the initialization function reports success, so the VMBus module is indeed loaded. VMBus functionality is not actually needed, but the VMBus module must be loaded so that hv_vmbus_exists() can answer correctly. Furthermore, the mshv_root dependency on the VMBus module is needed as described in the commit message for 840b740a35bf ("mshv: Add conditional VMBus dependency").

Loading the VMBus module without actually initializing it causes failures if the module should later be unloaded. The module unload code tries to clean up things that were never initialized, resulting in memory faults and a panic.

Fix this by having VMBus module exit function perform the same check for non-nested root partition, and do nothing in such a case, just like hv_acpi_init().

In the long run, the code that manages the Hyper-V provided SynIC should be refactored to better coordinate the requirements of root partition scenarios and normal VM scenarios, and to hopefully remove the hv_vmbus_exists() dependnecy between mshv_root and VMBus modules. Preventing the current unload failure scenario is an expediency until such a refactoring is done.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.114, 6.18.52, 7.2.6, 7.3
  • linux Debian 13 6.12.115-2
  • linux Debian 14 7.2.6-1

debian advisories DEBIAN-CVE-2026-90097

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-90097

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.84.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.84.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1.150700.17.47.1

suse advisories SUSE-SU-2026:4706-1SUSE-SU-2026:4640-1SUSE-SU-2026:24316-1SUSE-SU-2026:24315-1SUSE-SU-2026:24181-1SUSE-SU-2026:24182-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.39.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.39.1

opensuse advisories openSUSE-SU-2026:22091-1openSUSE-SU-2026:11880-1

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-102971

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-90097 updated cvss 5.5

kernel: Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.