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Vulnerability record · CVE-2021-22543 · published 26 May 2021

CVE-2021-22543: Linux kernel memory buffer overflow vulnerability

Linux · Linux Kernel

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.

8.7 CVSS 4.0 High EPSS 0.66% · top 50.4% CWE-119 · Memory buffer overflow
8.7CVSS 4.0 base score, v2 4.6
0.66%EPSS exploitation probability, 30 days
NoNot in CISA KEV
13Affected product versions listed by NVD
14References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

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:

Affected products

13 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/06/26/1 Mailing List
https://github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584 ExploitThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4G5YBUVEPHZYXMKNGBZ3S6I
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ROQIXQB7ZAWI3KSGSHR6H5R
https://security.netapp.com/advisory/ntap-20210708-0002/ Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/06/26/1 Mailing List
https://github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584 ExploitThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4G5YBUVEPHZYXMKNGBZ3S6I
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ROQIXQB7ZAWI3KSGSHR6H5R
https://security.netapp.com/advisory/ntap-20210708-0002/ Third Party Advisory

Track CVE-2021-22543 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

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Source: NIST National Vulnerability Database (record CVE-2021-22543), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.