CVE WatchAug 12, 2026

CVE-2021-21985

VMware vCenter Server Improper Input Validation Vulnerability

CVSS

9.8

Critical

EPSS

100.0%

p100

KEV

YES

Nov 3, 2021

Exploit Today

0-100

Published: May 26, 2021 · Last modified: Aug 12, 2026 · CWE-918 · CWE-20 · CWE-470

EPSS · 30d

100.0%EPSS · 30 days100.0%

2026-09-162026-10-14

KEV catalog record

Product

VMware / vCenter Server

Vulnerability

VMware vCenter Server Improper Input Validation Vulnerability

Added to KEV

Nov 3, 2021

Remediate by

Nov 17, 2021

Known ransomware use

Yes

Summary description

VMware vSphere Client contains an improper input validation vulnerability in the Virtual SAN Health Check plug-in, which is enabled by default in vCenter Server, which allows for remote code execution.

Required action

Apply updates per vendor instructions.

Notes

https://nvd.nist.gov/vuln/detail/CVE-2021-21985

Technical description

The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. 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.

Official references

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