Microsoft Security Response Center guidance
Vendor revision: Oct 20, 2026Release Notes
Vulnerability intelligence
CVE-2026-98720. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
Release Notes
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified
Force a refresh of the vmcs02 MSR bitmap during nested VM-Enter if the runtime eVMCS controls (pin, primary, secondary, etc.) are being updated. If L1 isn't intercepting TPR writes, runs L2 with TPR virtualization, and then runs the same L2 with TPR virtualization disabled, KVM will fail to refresh msr_bitmap02 and leave TPR in passthrough mode even though TPR virtualization is disabled.
I.e. failure to refresh the bitmap lets L2 (or L1 by proxy) read and write L0's TPR.
Source: NVD