---
id: CVE-2026-46071
title: 'KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12

  svm_copy_lbrs() always marks VMCB_LBR dirty in the destination VMCB.
  However, nested_svm_vmexit() uses it to copy LBRs to …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <
    165b08d2d1346dce5ed43db65e10f3194b9ae2fe
  - >-
    Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <
    11d347b7edf5093d69aca72317300798a32bfd6b
  - >-
    Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <
    a3f0981a5a0e0bd51ad74cc7d9eed32294b24002
  - >-
    Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <
    9efe23568806d1cd06f7d146f9b3037b8d585a9f
  - >-
    Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <
    b53ab5167a81537777ac780bbd93d32613aa3bda
  - Linux 5.19
published: '2026-05-27'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:41:17.270Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-46071'
references:
  - url: 'https://git.kernel.org/stable/c/165b08d2d1346dce5ed43db65e10f3194b9ae2fe'
  - url: 'https://git.kernel.org/stable/c/11d347b7edf5093d69aca72317300798a32bfd6b'
  - url: 'https://git.kernel.org/stable/c/a3f0981a5a0e0bd51ad74cc7d9eed32294b24002'
  - url: 'https://git.kernel.org/stable/c/9efe23568806d1cd06f7d146f9b3037b8d585a9f'
  - url: 'https://git.kernel.org/stable/c/b53ab5167a81537777ac780bbd93d32613aa3bda'
tags:
  - cve.org
epss: 0.0016
epssPercentile: 0.04793
ingestedAt: '2026-10-21T12:48:53.631Z'
---

## Overview

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

KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12

svm_copy_lbrs() always marks VMCB_LBR dirty in the destination VMCB.
However, nested_svm_vmexit() uses it to copy LBRs to vmcb12, and
clearing clean bits in vmcb12 is not architecturally defined.

Move vmcb_mark_dirty() to callers and drop it for vmcb12.

This also facilitates incoming refactoring that does not pass the entire
VMCB to svm_copy_lbrs().

## Affected

- `Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e < 165b08d2d1346dce5ed43db65e10f3194b9ae2fe`
- `Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e < 11d347b7edf5093d69aca72317300798a32bfd6b`
- `Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e < a3f0981a5a0e0bd51ad74cc7d9eed32294b24002`
- `Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e < 9efe23568806d1cd06f7d146f9b3037b8d585a9f`
- `Linux >= d20c796ca3709801f8a7fa36e8770a3dd8ebd34e < b53ab5167a81537777ac780bbd93d32613aa3bda`
- `Linux 5.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.