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CVE Record

CVE-2024-46864: x86/hyperv: fix kexec crash due to VP assist page corruption

In the Linux kernel, the following vulnerability has been resolved: x86/hyperv: fix kexec crash due to VP assist page corruption commit 9636be85cc5b ("x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline") introduces a new cpuhp state for hyperv initialization. cpuhp_setup_state() returns the state number if state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN and 0 for all other states. For the hyperv case, since a new cpuhp state was introduced it would return 0. However, in hv_machine_shutdown(), the cpuhp_remove_state() call is conditioned upon "hyperv_init_cpuhp > 0". This will never be true and so hv_cpu_die() won't be called on all CPUs. This means the VP assist page won't be reset. When the kexec kernel tries to setup the VP assist page again, the hypervisor corrupts the memory region of the old VP assist page causing a panic in case the kexec kernel is using that memory elsewhere. This was originally fixed in commit dfe94d4086e4 ("x86/hyperv: Fix kexec panic/hang issues"). Get rid of hyperv_init_cpuhp entirely since we are no longer using a dynamic cpuhp state and use CPUHP_AP_HYPERV_ONLINE directly with cpuhp_remove_state().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash a Linux system running on Microsoft Hyper-V during a kexec reboot. The failure comes from stale Hyper-V VP assist page state that is not reset before the next kernel starts. The practical business impact is availability risk during kernel handoff or reboot workflows, not confirmed remote compromise.

Executive priority

Treat as a targeted availability risk for Linux-on-Hyper-V environments. Prioritize patch validation where kexec supports uptime, incident response, or crash recovery. Broad emergency response is not supported by the provided sources because exploitation is not reported and severity scoring is absent.

Technical view

A Hyper-V x86 CPU hotplug initialization change left cpuhp_remove_state() gated on a value that never became positive. As a result, hv_cpu_die() did not reset VP assist pages on shutdown. During kexec, Hyper-V could corrupt the old VP assist page memory, causing panic or hang in the new kernel.

Likely exposure

Exposure appears limited to Linux kernels with the affected Hyper-V x86 code path, especially guests running on Hyper-V that use kexec-based reboot or crash-recovery workflows. The source bundle lists Linux kernel versions and stable commits, but distro-specific package mapping is not provided.

Exploitation context

The sources do not report active exploitation, and KEV is false. The described trigger is operational: a kexec kernel setup after improper Hyper-V VP assist page cleanup. No public exploit path, privilege requirement, or remote attack vector is established in the provided evidence.

Researcher notes

The key defect is lifecycle cleanup, not a general memory corruption primitive in user workloads. Analysis should focus on Hyper-V guest shutdown/kexec paths, CPU hotplug state registration, and whether downstream kernels backported the cpuhp_remove_state() fix.

Mitigation direction

  • Update to a Linux kernel containing the referenced stable fix commits.
  • Check distribution advisories for exact fixed package versions.
  • Prioritize Hyper-V Linux guests using kexec or crash-kernel workflows.
  • Review vendor guidance before applying temporary operational workarounds.

Validation and detection

  • Inventory Linux guests running on Hyper-V and their kernel versions.
  • Determine whether each kernel includes the referenced stable fix commits.
  • Identify systems using kexec, fast reboot, or crash dump kernel paths.
  • Review reboot and panic logs for kexec-related Hyper-V failures.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux9636be85cc5bdd8b7a7f6a53405cbcc52161c93c, 9636be85cc5bdd8b7a7f6a53405cbcc52161c93c, 9636be85cc5bdd8b7a7f6a53405cbcc52161c93cunaffected
LinuxLinux6.4, 0, 6.6.52, 6.10.11, 6.11affected
Weakness

CWE details

No CWE listed

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