Vulnerability Intelligence Report
VMware vCenter Server Improper Input Validation Vulnerability
CVE-2021-21985
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.
CISA KEV
Nuclei Template
SSVC: Active Exploitation
Automatable
CVSS Base Score
9.8
CRITICAL
Exploitability:3.9
Impact Score:5.9
EPSS Probability:100.00%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-20 ↗CWE-20 Improper Input Validation
CWE-470 ↗CWE-470 Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
CWE-918 ↗CWE-918 Server-Side Request Forgery (SSRF)
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| n/a | VMware vCenter Server and VMware Cloud Foundation | VMware vCenter Server (7.x before 7.0 U2b, 6.7 before 6.7 U3n, 6.5 before 6.5 U3p) and VMware Cloud Foundation (4.x before 4.2.1, 3.x before 3.10.2.1) (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
CISA KEV
ACTIVE IN CATALOG
Nuclei Template
SCANNER AVAILABLE
EPSS Score
99.999%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | VMware by Broadcom · Vendor · USA |
| Reserved | 2021-01-04T00:00:00 |
| Published | 2021-05-26T14:04:30 |
| Last Updated | 2026-08-12T03:55:45 |
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