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Linux KVM nVMX Frees Shadow VMCS Before Clearing the vmcs01 Pointer, Racing with Migration-Triggered VMCLEAR

Last refreshed2026-09-30

Status: NEW  |  Advisory ID: CVE-2026-64562

Key Details

CVECVE-2026-64562
CVSS Score / Version8.8 (High) / CVSS v3.1
Updated2026-08-19
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS Proseattack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is changed; confidentiality impact is high; integrity impact is high; availability impact is high.

What to Know

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

KVM: nVMX: Hide shadow VMCS right after VMCLEAR

free_nested() frees the shadow VMCS while vmcs01 still points to it. But

because it is asynchronous with respect to loaded_vmcs_clear(), the vCPU

might migrate before the pointer is cleared and __loaded_vmcs_clear()

may then execute VMCLEAR.

The VMCS needs to stay attached until its explicit VMCLEAR completes, but

then it can be hidden and the page safely freed. (NVD)

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-64562
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-64562