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…
- Published
- Updated
- Reserved
- Assigned by
- vmware
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as VMware vCenter Server Improper Input Validation Vulnerability.
- Added
- 3 Nov 2021
- Fix due (US federal)
- 17 Nov 2021
- Used by ransomware
- Known
Apply updates per vendor instructions.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 100.0% · top 0.1% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Weakness
- Remote code execution vulnerability
- CWE-20 Improper Input Validation (opens in a new tab)All about CWE-20 and its CVEs
- CWE-470 Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') (opens in a new tab)All about CWE-470 and its CVEs
- CWE-918 Server-Side Request Forgery (SSRF) (opens in a new tab)All about CWE-918 and its CVEs
Affected products
VMware vCenter Server and VMware Cloud Foundation
- affected 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)
References (4)
- https://www.vmware.com/security/advisories/VMSA-2021-0010.html (opens in a new tab)x_refsource_MISCx_transferred
- http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html (opens in a new tab)x_refsource_MISCx_transferred
- http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-21985)Record last updated .