Is CVE-2021-3631 in the CISA KEV catalog?

No. CVE-2021-3631 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-3631?

CVE-2021-3631 has a CVSS v3 base score of 6.3 (MEDIUM).

What is the EPSS score for CVE-2021-3631?

CVE-2021-3631 has an EPSS score of 0.49% (39th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-3631?

Upgrade libvirt on debian 11 to 7.0.0-3+deb11u3 or later. Fixes are available for 5 affected products.

CVE & CISA-KEV Catalog

CVE-2021-3631

MEDIUM

6.3

CVSS v3

NVD

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.

CWE-732Incorrect Permission Assignment for Critical Resource

How to fix

Remediation Available

libvirtDebian

Fixed in:7.0.0-3+deb11u3CVE-2021-3631

Fixed in:7.6.0-1CVE-2021-3631

libvirtUbuntu

Fixed in:4.0.0-1ubuntu8.21USN-5399-1

Fixed in:6.0.0-0ubuntu8.16USN-5399-1

libvirt-daemonUbuntu

Fixed in:4.0.0-1ubuntu8.21USN-5399-1

Fixed in:6.0.0-0ubuntu8.16USN-5399-1

libvirt-daemon-systemUbuntu

Fixed in:4.0.0-1ubuntu8.21USN-5399-1

Fixed in:6.0.0-0ubuntu8.16USN-5399-1

libvirt0Ubuntu

Fixed in:4.0.0-1ubuntu8.21USN-5399-1

Fixed in:6.0.0-0ubuntu8.16USN-5399-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.49%probability of exploitation in 30 days

39thpercentile

Low risk: more likely to be exploited than 39% of all known CVEs.

References

Patch1

gitlab.com

Exploit1

gitlab.com

Vendor Advisory2

Third-Party Advisory2

Other references1

lists.debian.org

Related Vulnerabilities

Other CWE-732 (Incorrect Permission Assignment for Critical Resource) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2011-3923	Critical	9.8	89%	-	Fix
CVE-2018-15379	Critical	9.8	86%	-	-
CVE-2018-1000207	High	7.2	64%	-	-
CVE-2023-32986	High	8.8	63%	-	-
CVE-2021-44521	Critical	9.1	55%	-	Fix
CVE-2018-13374	Medium	4.3	38%	KEV + Ransom	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.