CVE-2021-22543

Name: CVE-2021-22543
Creator: NVD / NIST
Published: 2021-05-26T11:15:08.623+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 0.66%

Last modified Jun 17, 2026

CVE-2021-22543 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation.. EPSS estimates a 0.66% chance of exploitation in the next 30 days.

Description

An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

8.7/10

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.66%

46.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	2021-05-18
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34
Debian	Debian Linux	9.0
Netapp	H410c Firmware	All versions
Netapp	H300s Firmware	All versions
Netapp	H500s Firmware	All versions
Netapp	H700s Firmware	All versions
Netapp	H300e Firmware	All versions
Netapp	H500e Firmware	All versions
Netapp	H700e Firmware	All versions
Netapp	H410s Firmware	All versions
Netapp	Cloud Backup	All versions
Netapp	Solidfire Baseboard Management Controller Firmware	All versions

References

http://www.openwall.com/lists/oss-security/2021/06/26/1Mailing List
https://github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4G5YBUVEPHZYXMKNGBZ3S6INFCTEEL4E/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ROQIXQB7ZAWI3KSGSHR6H5RDUWZI775S/
https://security.netapp.com/advisory/ntap-20210708-0002/Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/06/26/1Mailing List
https://github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4G5YBUVEPHZYXMKNGBZ3S6INFCTEEL4E/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ROQIXQB7ZAWI3KSGSHR6H5RDUWZI775S/
https://security.netapp.com/advisory/ntap-20210708-0002/Third Party Advisory

Timeline

Published: May 26, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-22543?

How severe is CVE-2021-22543?

CVE-2021-22543 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.66% probability of exploitation in the next 30 days.

How do I fix CVE-2021-22543?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-22543?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST