Cloudanix VulnDB

CVE-2023-53647

Medium · 5.5

CVSS

5.5

EPSS

0.2%

Published

Oct 7, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in the Linux kernel can make virtual machines crash while starting up when running on certain virtualization platforms.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Memory Corruption
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

NULL pointer dereference in ACPI namespace lookup during VMBus platform driver probe when ACPI root object handle is dereferenced after failing to locate Hyper-V MMIO ranges, resulting in kernel oops on boot for non-standard VMBus ACPI implementations.

Why it matters to the business

Linux guests on certain hypervisors may fail to boot, causing unplanned downtime and reduced availability for virtualized workloads; high downstream prevalence in cloud and container environments increases operational risk.

How an attack unfolds

An attacker with local access or control over boot configuration triggers the vulnerable driver path on systems using VMBus implementations without provided MMIO ranges; the kernel panics during ACPI resource walk, denying service. No remote code execution or privilege escalation path exists from this flaw alone.

How to fix it

Upgrade to a fixed Linux kernel version that terminates the ACPI lookup before reaching the root object; apply vendor backports for the hv_vmbus driver. Reboot after update and verify VMBus functionality under affected hypervisors.

How to confirm the fix worked

Confirm kernel version contains the explicit root-object termination fix; reproduce boot under QEMU VMBus or equivalent; monitor dmesg for absence of the acpi_ns_lookup page fault during vmbus_platform_driver_probe.

Typical attack path

  1. Gain local access or modify boot parameters on target Linux guest
  2. Ensure VMBus ACPI device lacks Hyper-V MMIO ranges in namespace
  3. Trigger driver load during boot or module insertion
  4. Cause ACPI namespace walk to reach root object handle
  5. Trigger NULL dereference and kernel oops

How to detect it

Review kernel logs and dmesg for page_fault_oops or acpi_ns_lookup failures during hv_vmbus initialization; search boot logs for vmbus_platform_driver_probe stack traces on affected systems.

What your security team should do

  • Prioritize kernel updates on all Linux guests using Hyper-V or VMBus on non-Microsoft hypervisors
  • Test boot stability in lab environments matching production hypervisor stack before rollout
  • Monitor EPSS trend and kernel mailing list for related ACPI/VMBus patches

The record

In the Linux kernel, the following vulnerability has been resolved: Drivers: hv: vmbus: Don't dereference ACPI root object handle Since the commit referenced in the Fixes: tag below the VMBus client driver is walking the ACPI namespace up from the VMBus ACPI device to the ACPI namespace root object trying to find Hyper-V MMIO ranges. However, if it is not able to find them it ends trying to walk resources of the ACPI namespace root object itself. This object has all-ones handle, which causes a NULL pointer dereference in the ACPI code (from dereferencing this pointer with an offset). This in turn causes an oops on boot with VMBus host implementations that do not provide Hyper-V MMIO ranges in their VMBus ACPI device or its ancestors. The QEMU VMBus implementation is an example of such implementation. I guess providing these ranges is optional, since all tested Windows versions seem to be able to use VMBus devices without them. Fix this by explicitly terminating the lookup at the ACPI namespace root object. Note that Linux guests under KVM/QEMU do not use the Hyper-V PV interface by default - they only do so if the KVM PV interface is missing or disabled. Example stack trace of such oops: [ 3.710827] ? __die+0x1f/0x60 [ 3.715030] ? page_fault_oops+0x159/0x460 [ 3.716008] ? exc_page_fault+0x73/0x170 [ 3.716959] ? asm_exc_page_fault+0x22/0x30 [ 3.717957] ? acpi_ns_lookup+0x7a/0x4b0 [ 3.718898] ? acpi_ns_internalize_name+0x79/0xc0 [ 3.720018] acpi_ns_get_node_unlocked+0xb5/0xe0 [ 3.721120] ? acpi_ns_check_object_type+0xfe/0x200 [ 3.722285] ? acpi_rs_convert_aml_to_resource+0x37/0x6e0 [ 3.723559] ? down_timeout+0x3a/0x60 [ 3.724455] ? acpi_ns_get_node+0x3a/0x60 [ 3.725412] acpi_ns_get_node+0x3a/0x60 [ 3.726335] acpi_ns_evaluate+0x1c3/0x2c0 [ 3.727295] acpi_ut_evaluate_object+0x64/0x1b0 [ 3.728400] acpi_rs_get_method_data+0x2b/0x70 [ 3.729476] ? vmbus_platform_driver_probe+0x1d0/0x1d0 [hv_vmbus] [ 3.730940] ? vmbus_platform_driver_probe+0x1d0/0x1d0 [hv_vmbus] [ 3.732411] acpi_walk_resources+0x78/0xd0 [ 3.733398] vmbus_platform_driver_probe+0x9f/0x1d0 [hv_vmbus] [ 3.734802] platform_probe+0x3d/0x90 [ 3.735684] really_probe+0x19b/0x400 [ 3.736570] ? __device_attach_driver+0x100/0x100 [ 3.737697] __driver_probe_device+0x78/0x160 [ 3.738746] driver_probe_device+0x1f/0x90 [ 3.739743] __driver_attach+0xc2/0x1b0 [ 3.740671] bus_for_each_dev+0x70/0xc0 [ 3.741601] bus_add_driver+0x10e/0x210 [ 3.742527] driver_register+0x55/0xf0 [ 3.744412] ? 0xffffffffc039a000 [ 3.745207] hv_acpi_init+0x3c/0x1000 [hv_vmbus]

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 4.3.0 6.1.53
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise High Availability Extension 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_17 0 1-150600.1.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_17 0 1-150600.13.5.1
SUSE:Linux Enterprise Live Patching 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_6 0 1-150700.15.3.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-64kb 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default-base 0 6.4.0-150600.23.78.1.150600.12.34.2
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-source 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-zfcpdump 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-64kb 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-default-base 0 6.4.0-150700.53.22.1.150700.17.15.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-source 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-zfcpdump 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-docs 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-obs-build 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-source 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-syms 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-docs 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-obs-build 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-source 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-syms 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Legacy 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Module for Legacy 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-azure 0 6.4.0-150600.8.55.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure 0 6.4.0-150600.8.55.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-syms-azure 0 6.4.0-150600.8.55.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-source-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-syms-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Workstation Extension 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise Workstation Extension 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Real Time Module 15 SP6 kernel-rt 0 6.4.0-150600.10.58.1
SUSE:Real Time Module 15 SP6 kernel-rt_debug 0 6.4.0-150600.10.58.1
SUSE:Real Time Module 15 SP6 kernel-source-rt 0 6.4.0-150600.10.58.1
SUSE:Real Time Module 15 SP6 kernel-syms-rt 0 6.4.0-150600.10.58.1
openSUSE:Leap 15.6 dtb-aarch64 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-64kb 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-azure 0 6.4.0-150600.8.55.1
openSUSE:Leap 15.6 kernel-debug 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-default 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-default-base 0 6.4.0-150600.23.78.1.150600.12.34.2
openSUSE:Leap 15.6 kernel-docs 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-kvmsmall 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-obs-build 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-obs-qa 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-rt 0 6.4.0-150600.10.58.1
openSUSE:Leap 15.6 kernel-rt_debug 0 6.4.0-150600.10.58.1
openSUSE:Leap 15.6 kernel-source 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-source-azure 0 6.4.0-150600.8.55.1
openSUSE:Leap 15.6 kernel-source-rt 0 6.4.0-150600.10.58.1
openSUSE:Leap 15.6 kernel-syms 0 6.4.0-150600.23.78.1
openSUSE:Leap 15.6 kernel-syms-azure 0 6.4.0-150600.8.55.1
openSUSE:Leap 15.6 kernel-syms-rt 0 6.4.0-150600.10.58.1
openSUSE:Leap 15.6 kernel-zfcpdump 0 6.4.0-150600.23.78.1

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