CVE-2017-12154: The prepare_vmcs02 function in arch/x86/kvm/vmx.c in the Linux kernel through 4.13.3 does not ensure that t...

Security readout for executives and security teams

This Linux KVM flaw affects nested virtualization. A guest running inside another guest could access the physical CPU CR8 register when KVM should have intercepted that access. The main business concern is hypervisor isolation on older Linux kernels, especially platforms that allow customers or tenants to run nested virtual machines. Exposure is most likely on Linux KVM hosts running kernels through 4.13.3 with Intel VMX nested virtualization enabled. Systems not using KVM, not using nested virtualization, or already updated through vendor kernel advisories are less likely to be exposed. Treat this as a targeted infrastructure risk, not a broad internet-facing emergency. Prioritize patching KVM virtualization hosts that support nested guest workloads or untrusted tenants. Routine servers without nested KVM exposure should follow normal kernel maintenance cadence. Mitigation focus: Apply vendor kernel updates from Debian, Ubuntu, or Red Hat advisories where applicable.; Confirm the running kernel includes upstream commit 51aa68e7d57e or an equivalent backport.; Disable nested KVM virtualization where it is not operationally required..

Prepared

Jun 12, 2026, 20:56 UTC (UTC+00:00)

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