CVE-2021-21985: VMware vCenter Server Improper Input Validation Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 100% chance of exploitation in the next 30 days.

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.

Affected products

• VMware Cloud Foundation: from 3.0, before 3.10.2.1 (fixed in 3.10.2.1); from 4.0, before 4.2.1 (fixed in 4.2.1)
• VMware vCenter Server: version 6.5 only; version 6.7 only; version 7.0 only

Published 2021-05-26. Last modified 2026-08-12.