CVE-2021-21985: listed in the CISA KEV catalog

CVE-2021-21985 · CVSS 9.8 CRITICAL · EPSS 100.0% · KEV 2021-11-03

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.

Is CVE-2021-21985 exploited?

• Listed in the CISA KEV catalog on 2021-11-03.
• Federal remediation due 2021-11-17.
• Past that date by 1732 days.
• Used in ransomware campaigns.
• EPSS puts exploitation in the next 30 days at 100.0%.
• Public exploit code: packaged in a public tool.
• Public detection rules exist.

Which products and versions are affected?

No affected package list recorded here yet.

Is there a patch?

No patch identifier recorded here yet.

What PlainSec published about CVE-2021-21985

• Node Kernel Bugs on GKE COS Nodes Enable Host Escalation (2026-04-15)
• Google Cloud Issues Multiple Linux Kernel Privilege Escalation Fixes for GKE Nodes (2026-04-07)
• Multiple Linux Kernel Flaws Elevate Privileges on GCP Container Nodes (2026-04-03)
• Multiple High-Severity Cloud Vulnerabilities Impact Container Nodes (2026-04-01)

Primary sources

• NVD record
• CISA KEV catalog
• Metasploit: exploit/linux/http/vmware_vcenter_vsan_health_rce
• Nuclei template

What this record does not say

• No affected package data.
• No patch identifier.

KEV and EPSS are re-checked daily. Record last updated 2026-08-15.