---
id: CVE-2020-36311
title: An issue was discovered in the Linux kernel before 5.9
summary: >-
  An issue was discovered in the Linux kernel before 5.9. arch/x86/kvm/svm/sev.c
  allows attackers to cause a denial of service (soft lockup) by triggering
  destruction of a large SEV VM (which requires unregistering many encrypted
  regions),…
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 < 5.9.0
  - debian_linux = 9.0
  - debian_linux = 10.0
patched:
  - linux_kernel 5.9.0
published: '2021-04-07'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:29.923'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-36311'
references:
  - url: 'https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9'
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7be74942f184fdfba34ddd19a0d995deb34d4a03
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html'
    label: cve@mitre.org
  - url: 'https://www.debian.org/security/2021/dsa-4941'
    label: cve@mitre.org
  - url: 'https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7be74942f184fdfba34ddd19a0d995deb34d4a03
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2021/dsa-4941'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2020/cve-2020-36311.json
  - url: 'https://access.redhat.com/security/cve/CVE-2020-36311'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1947994'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2020-36311'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2020-36311'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00335
epssPercentile: 0.27069
ingestedAt: '2026-10-08T22:11:53.731Z'
scores:
  nvd: 5.5
  vendor: 2.8
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-08T21:00:35.710173Z'
---

## Overview

An issue was discovered in the Linux kernel before 5.9. arch/x86/kvm/svm/sev.c allows attackers to cause a denial of service (soft lockup) by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions), aka CID-7be74942f184.

## Affected

- `linux_kernel < 5.9.0`
- `debian_linux = 9.0`
- `debian_linux = 10.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.9.0`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 8 · no fix planned: Red Hat Enterprise Linux 8 · updated 2026-10-08 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2020/cve-2020-36311.json)