CVE-2021-3631: A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels

This month

MEDIUM 6.3WATCHLISTUPGRADEDOWNGRADEMITIGATE

CVE-2021-3631 is a medium-severity flaw (CVSS 6.3) affecting libvirt, openshift container platform, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.3 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-732
Published	2022-03-02
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: netapp · redhat

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-03-02 23:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

redhat libvirt UPGRADE

Affected: < 7.5.0

Fixed in: 7.5.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libvirt || rpm -q libvirt || libvirt --version

2. UPGRADE to 7.5.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libvirt

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libvirt

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat openshift container platform DOWNGRADE

Affected: 4.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.8

1. Check installed version

apt-cache policy openshift-container-platform || rpm -q openshift-container-platform || openshift-container-platform --version

2. No fixed release: DOWNGRADE to a release before 4.8 (Debian / Ubuntu)

apt-cache madison openshift-container-platform sudo apt install openshift-container-platform=<VERSION_BEFORE_4.8> sudo apt-mark hold openshift-container-platform

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-container-platform sudo dnf downgrade openshift-container-platform-<VERSION_BEFORE_4.8> sudo dnf versionlock add openshift-container-platform

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat enterprise linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

netapp ontap select deploy administration utility MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ontap-select-deploy-administration-utility || rpm -q ontap-select-deploy-administration-utility || ontap-select-deploy-administration-utility --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-3631?

libvirt: upgrade to 7.5.0; openshift container platform: downgrade or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-3631 being exploited?

CVE-2021-3631 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-3631 affect?

CVE-2021-3631 affects libvirt, openshift container platform, enterprise linux. Severity is medium (CVSS 6.3). 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 highe

How urgent is CVE-2021-3631?

Priority 43/100. Public exploit reference; On your watchlist

Software pages

Red Hat OpenShift vulnerabilities

Related CVEs

CVE-2024-8235 MEDIUM 6.2 UPGRADE A flaw was found in libvirt
CVE-2024-2496 MEDIUM 5.0 UPGRADE MITIGATE A NULL pointer dereference flaw was found in the udevConnectListAllInterfaces() function in libvirt
CVE-2023-3750 MEDIUM 6.5 MITIGATE MITIGATE A flaw was found in libvirt
CVE-2023-2700 MEDIUM 5.5 DOWNGRADE MITIGATE A vulnerability was found in libvirt
CVE-2022-0897 MEDIUM 4.3 UPGRADE MITIGATE A flaw was found in the libvirt nwfilter driver

References

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