CVE-2021-21985
VMware vCenter Server Improper Input Validation Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 100.00% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 November 2021 · due 17 November 2021 · used in ransomware campaigns
- Weakness
- CWE-918, CWE-20, CWE-470
- Affected
- vmware/vcenter server · vmware/cloud foundation
- Source
- security@vmware.com
EPSS 100.0% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-21985
References
- http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.htmlThird Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- https://www.vmware.com/security/advisories/VMSA-2021-0010.htmlVendor Advisory
- http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.htmlThird Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- https://www.vmware.com/security/advisories/VMSA-2021-0010.htmlVendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.