SB20261022321 - Protection mechanism failure in Linux kernel kvm svm

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Main Vulnerability Database SB20261022321

SB20261022321 - Protection mechanism failure in Linux kernel kvm svm

Published: October 22, 2026

Security Bulletin ID SB20261022321
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Protection mechanism failure (CVE-ID: CVE-2026-98716)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to interfere with correct handling of model-specific register state in nested virtual machines, potentially weakening isolation between execution contexts.

The vulnerability exists due to incorrect selection of the MSR permission bitmap in KVM's SVM msr_write_intercepted() function when checking MSR write interception while a nested guest is active. A local user can trigger nested guest MSR accesses to cause interception checks to consult vmcb02's bitmap even when it is not the active virtual machine control block's bitmap, potentially resulting in incorrect MSR state handling.


Remediation

Install update from vendor's website.

References