Is CVE-2021-21972 in the CISA KEV catalog?

Yes. CVE-2021-21972 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03, and has known ransomware campaign use.

What is the CVSS severity of CVE-2021-21972?

CVE-2021-21972 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-21972?

CVE-2021-21972 has an EPSS score of 99.57% (100th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21972?

Upgrade cloud foundation to 4.2 or later.

CVE & CISA-KEV Catalog

CVE-2021-21972

CRITICALCISA KEVEPSS 100th pctl

9.8

CVSS v3

NVD

Description

The vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server. This affects VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).

CWE-22Path Traversal

How to fix

Remediation Available

cloud foundationNVD

Affected:>= 4.0, < 4.2Fixed in:4.2CVE-2021-21972derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

99.57%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

VMware vCenter Server Remote Code Execution Vulnerability

VMware vCenter Server vSphere Client contains a remote code execution vulnerability in a vCenter Server plugin which allows an attacker with network access to port 443 to execute commands with unrestricted privileges on the underlying operating system.

Apply updates per vendor instructions.

Remediation due: 2021-11-17

Associated with ransomware campaigns

References

Exploit3

Vendor Advisory1

vmware.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-22 (Path Traversal) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-23897	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-32315	High	8.6	100%	KEV	Fix
CVE-2022-29464	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-26086	Medium	5.3	100%	KEV	Fix
CVE-2021-22005	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-5902	Critical	9.8	100%	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 2025-10-30.