CVE-2026-98716

Received Received - Intake

KVM MSR Interception Vulnerability in Linux Kernel

Publication date: 2026-10-18

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Use the active VMCB's MSR bitmap when checking if MSR is intercepted Use the MSR permission bitmap of the active VMCB instead of assuming that KVM is always using vmcb02's bitmap when L2 is active, as KVM uses msrpm02 if and only if L1 wants to intercept MSR accesses, i.e. if and only if KVM needs to merge msprm01 with msrpm12. Don't bother tracking the virtual address of the bitmap that's being used, as __va() is cheap on x86, and caching the virtual address would introduce yet another source of potentially stale information.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-18

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-18

EPSS Evaluated

N/A

NVD

CVE-2026-98716

EUVD

EUVD-2026-103970

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	b2ac58f90540e39324e7a29a7ad471407ae0bf48
Linux	Linux	b2ac58f90540e39324e7a29a7ad471407ae0bf48
Linux	Linux	b2ac58f90540e39324e7a29a7ad471407ae0bf48
Linux	Linux	b2ac58f90540e39324e7a29a7ad471407ae0bf48
Linux	Linux	f54d0bb8487d2f016fbc4f0e38ef9098f8eb8bd4
Linux	Linux	89be8950bab799ddb9cc3777345e3c21bcb32dba
Linux	Linux	3.16.57
Linux	Linux	4.4.168
Linux	Linux	4.16

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves KVM (Kernel-based Virtual Machine) for AMD processors. It occurs when checking if a Model-Specific Register (MSR) is intercepted. The issue arises because the system incorrectly uses the MSR permission bitmap of vmcb02 (a virtual machine control block) even when L2 (a nested virtual machine) is active, instead of using the active VMCB's bitmap. This can lead to improper handling of MSR access permissions.

Detection Guidance

This vulnerability is specific to the Linux kernel's KVM (Kernel-based Virtual Machine) SVM (Secure Virtual Machine) implementation. Detection requires checking the kernel version and KVM module behavior. Use 'uname -r' to check the kernel version and 'lsmod | grep kvm' to verify KVM modules are loaded. If vulnerable, update the kernel immediately.

Impact Analysis

This vulnerability could allow a guest virtual machine to gain unauthorized access to sensitive MSRs or bypass security controls. An attacker in a guest VM might exploit this to read or modify critical system settings, potentially leading to privilege escalation or denial of service on the host system.

Compliance Impact

The provided CVE data does not describe any direct impact on compliance with standards like GDPR or HIPAA. The vulnerability is specific to the Linux kernel's KVM module and involves MSR bitmap handling in virtualization environments, which does not inherently relate to data protection or privacy regulations.

Mitigation Strategies

Update the Linux kernel to the latest stable version that includes the fix for CVE-2026-98716. Monitor vendor advisories for patches and apply them promptly.

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