Is CVE-2021-3975 in the CISA KEV catalog?

No. CVE-2021-3975 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-3975?

CVE-2021-3975 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2021-3975?

CVE-2021-3975 has an EPSS score of 1.21% (65th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-3975?

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-2021-3975

MEDIUM

6.5

CVSS v3

NVD

Description

A use-after-free flaw was found in libvirt. The qemuMonitorUnregister() function in qemuProcessHandleMonitorEOF is called using multiple threads without being adequately protected by a monitor lock. This flaw could be triggered by the virConnectGetAllDomainStats API when the guest is shutting down. An unprivileged client with a read-only connection could use this flaw to perform a denial of service attack by causing the libvirt daemon to crash.

CWE-416Use After Free

How to fix

Remediation Available

libvirtDebian

Fixed in:7.0.0-3+deb11u3CVE-2021-3975

Fixed in:7.6.0-1CVE-2021-3975

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 VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

1.21%probability of exploitation in 30 days

65thpercentile

Moderate risk: more likely to be exploited than 65% of all known CVEs.

References

Patch3

Third-Party Advisory2

Other references1

lists.debian.org

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	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.