---
id: CVE-2021-38198
title: >-
  arch/x86/kvm/mmu/paging_tmpl.h in the Linux kernel before 5.12.11 incorrectly
  computes the access permissions of a shadow page, leading to a missing guest
  protection page fault.
summary: >-
  arch/x86/kvm/mmu/paging_tmpl.h in the Linux kernel before 5.12.11 incorrectly
  computes the access permissions of a shadow page, leading to a missing guest
  protection page fault.
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 5.12.11
  - debian_linux = 9.0
patched:
  - linux_kernel 5.12.11
published: '2021-08-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:39.163'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-38198'
references:
  - url: 'https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.11'
    label: cve@mitre.org
  - url: >-
      https://github.com/torvalds/linux/commit/b1bd5cba3306691c771d558e94baa73e8b0b96b7
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html'
    label: cve@mitre.org
  - url: 'https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.11'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/torvalds/linux/commit/b1bd5cba3306691c771d558e94baa73e8b0b96b7
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-38198.json
  - url: 'https://access.redhat.com/security/cve/CVE-2021-38198'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1992264'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2021-38198'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-38198'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.0045
epssPercentile: 0.3711
ingestedAt: '2026-10-08T22:11:53.739Z'
cwe:
  - CWE-732
scores:
  nvd: 5.5
  vendor: 6.4
---

## Overview

arch/x86/kvm/mmu/paging_tmpl.h in the Linux kernel before 5.12.11 incorrectly computes the access permissions of a shadow page, leading to a missing guest protection page fault.

## Affected

- `linux_kernel < 5.12.11`
- `debian_linux = 9.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.12.11`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8 · updated 2026-10-08 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-38198.json)