KVM Vulnerability in Linux Kernel Affecting Virtualization Environment

CVE-2026-64562

What is CVE-2026-64562?

A vulnerability exists within the KVM (Kernel-based Virtual Machine) implementation of the Linux kernel related to the management of shadow VMCS (Virtual Machine Control Structure). When the free_nested() function attempts to free the shadow VMCS while the vmcs01 pointer remains active, it can lead to conditions where the view of the virtual machine state becomes inconsistent. This flaw potentially allows asynchronous execution of VMCLEAR, which can be executed on an incorrect VMCS state if the virtual CPU (vCPU) migrates before the cleanup process completes. The VMCS must remain linked until the VMCLEAR operation is explicitly finalized, ensuring safe memory management and stability in the virtualization environment.

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