Is CVE-2021-20237 in the CISA KEV catalog?

No. CVE-2021-20237 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-20237?

CVE-2021-20237 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-20237?

CVE-2021-20237 has an EPSS score of 1.69% (74th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-20237?

Upgrade zeromq3 on debian 11 to 4.3.3-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-20237

HIGHEPSS 74th pctl

7.5

CVSS v3

NVD

Description

An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3. This flaw allows a remote unauthenticated attacker to send crafted PUB messages that consume excessive memory if the CURVE/ZAP authentication is disabled on the server, causing a denial of service. The highest threat from this vulnerability is to system availability.

CWE-400Resource Exhaustion CWE-401Missing Release of Memory (Memory Leak)

How to fix

Remediation Available

zeromq3Debian

Fixed in:4.3.3-1CVE-2021-20237

libzmq3Ubuntu

Fixed in:4.0.4+dfsg-2ubuntu0.1+esm3USN-4920-1

libzmq5Ubuntu

Fixed in:4.1.4-7ubuntu0.1+esm2USN-4920-1

Fixed in:4.2.5-1ubuntu0.2+esm2USN-4920-1

Fixed in:4.3.2-2ubuntu1.20.04.1~esm2USN-4920-1

zeromq3Ubuntu

Fixed in:4.0.4+dfsg-2ubuntu0.1+esm3USN-4920-1

Fixed in:4.1.4-7ubuntu0.1+esm2USN-4920-1

Fixed in:4.2.5-1ubuntu0.2+esm2USN-4920-1

Fixed in:4.3.2-2ubuntu1.20.04.1~esm2USN-4920-1

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 RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

1.69%probability of exploitation in 30 days

74thpercentile

Elevated risk: more likely to be exploited than 74% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory1

bugzilla.redhat.com

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-44487	High	7.5	100%	KEV	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2011-3192	High	7.8	99%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2024-25617	Medium	5.3	89%	-	Fix
CVE-2018-1000115	High	7.5	89%	-	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.