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CVE-2026-98720

Опубликовано: 18 окт. 2026
Источник: redhat
CVSS3: 5.3
EPSS Низкий

Описание

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.

A flaw was found in the Linux kernel's KVM (Kernel-based Virtual Machine) nested virtualization implementation. This flaw allows an attacker within a nested guest to bypass isolation boundaries and directly access host hardware controls, potentially causing host system instability or a Denial of Service (DoS). The issue occurs when nested virtualization control settings are modified without refreshing internal register permissions, leaving the host's Task Priority Register (TPR) directly accessible to the guest.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Enterprise Linux 10kernelFix deferred
Red Hat Enterprise Linux 6kernelNot affected
Red Hat Enterprise Linux 7kernelNot affected
Red Hat Enterprise Linux 7kernel-rtNot affected
Red Hat Enterprise Linux 8kernelFix deferred
Red Hat Enterprise Linux 8kernel-rtFix deferred
Red Hat Enterprise Linux 9kernelFix deferred
Red Hat Enterprise Linux 9kernel-rtFix deferred
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-8Not affected
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-9Fix deferred

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Дополнительная информация

Статус:

Moderate
Дефект:
CWE-270
https://bugzilla.redhat.com/show_bug.cgi?id=2555141kernel: KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified

EPSS

Процентиль: 6%
0.00168
Низкий

5.3 Medium

CVSS3

Связанные уязвимости

ubuntu
23 дня назад

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.

nvd
23 дня назад

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.

CVSS3: 7.7
msrc
22 дня назад

KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified

debian
23 дня назад

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

github
23 дня назад

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.

EPSS

Процентиль: 6%
0.00168
Низкий

5.3 Medium

CVSS3