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
80
0-100
Published: May 26, 2021 · Last modified: Aug 12, 2026 · CWE-918 · CWE-20 · CWE-470
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
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.
- packetstormsecurity.comhttp://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html
- www.vmware.comhttps://www.vmware.com/security/advisories/VMSA-2021-0010.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html
- www.vmware.comhttps://www.vmware.com/security/advisories/VMSA-2021-0010.html
- www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985