CVE-2021-3631

Name: CVE-2021-3631
Creator: NVD / NIST
Published: 2022-03-02T23:15:08.677+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.3/10EPSS 0.49%

Last modified Jun 17, 2026

CVE-2021-3631 is a medium-severity vulnerability rated 6.3/10 on the CVSS scale. A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to access files labeled for another guest, resulting in the breaking out of sVirt confinement. EPSS estimates a 0.49% chance of exploitation in the next 30 days.

Description

A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to access files labeled for another guest, resulting in the breaking out of sVirt confinement. The highest threat from this vulnerability is to confidentiality and integrity.

Metrics

CVSS 3.1

6.3/10

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

EPSS Probability

0.49%

38.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Redhat	Libvirt	< 7.5.0
Redhat	Openshift Container Platform	4.8
Redhat	Enterprise Linux	8.0
Netapp	Ontap Select Deploy Administration Utility	All versions

References

https://access.redhat.com/errata/RHSA-2021:3631Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1977726Issue Tracking, Vendor Advisory
https://gitlab.com/libvirt/libvirt/-/commit/15073504dbb624d3f6c911e85557019d3620fdb2Patch, Third Party Advisory
https://gitlab.com/libvirt/libvirt/-/issues/153Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/04/msg00000.html
https://security.gentoo.org/glsa/202210-06Third Party Advisory
https://security.netapp.com/advisory/ntap-20220331-0010/Third Party Advisory
https://access.redhat.com/errata/RHSA-2021:3631Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1977726Issue Tracking, Vendor Advisory
https://gitlab.com/libvirt/libvirt/-/commit/15073504dbb624d3f6c911e85557019d3620fdb2Patch, Third Party Advisory
https://gitlab.com/libvirt/libvirt/-/issues/153Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/04/msg00000.html
https://security.gentoo.org/glsa/202210-06Third Party Advisory
https://security.netapp.com/advisory/ntap-20220331-0010/Third Party Advisory

Timeline

Published: Mar 2, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3631?

How severe is CVE-2021-3631?

CVE-2021-3631 has a CVSS score of 6.3/10 (MEDIUM severity). The EPSS model estimates a 0.49% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3631?

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-2021-3631?

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

Scan your code now

Source: NVD / NIST