CVE-2021-21972: VMware vCenter Server Remote Code Execution Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 252 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 99.9%
EPSS score, percentile 100 of all scored records
- How severe?
- 9.8 Critical
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . Apply updates per vendor instructions.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 7.x before 7.0 U1c
- 6.7 before 6.7 U3l
- 6.5 before 6.5 U3n
- 4.x before 4.2
- 3.x before 3.10.1.2
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 7.x before 7.0 U1c |
| Affected | 6.7 before 6.7 U3l |
| Affected | 6.5 before 6.5 U3n |
| Status | Versions |
|---|---|
| Affected | 4.x before 4.2 |
| Affected | 3.x before 3.10.1.2 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
VMware vCenter Server vSphere Client contains a remote code execution vulnerability in a vCenter Server plugin which allows an attacker with network access to port 443 to execute commands with unrestricted privileges on the underlying operating system.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2021-21972 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
- CISA marks it as known to be used in ransomware campaigns.
- The due date CISA sets for the required action is 17 Nov 2021.
- The CVE record was published on 24 Feb 2021, 252 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 99.9% (percentile 100), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
The vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin. 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. This affects VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited VMware vulnerabilities
- CVE-2025-22224: VMware ESXi and Workstation TOCTOU Race Condition Vulnerability
- CVE-2025-22225: VMware ESXi Arbitrary Write Vulnerability
- CVE-2025-22226: VMware ESXi, Workstation, and Fusion Information Disclosure Vulnerability
- CVE-2024-38812: VMware vCenter Server Heap-Based Buffer Overflow Vulnerability
- CVE-2024-38813: VMware vCenter Server Privilege Escalation Vulnerability
- CVE-2024-37085: VMware ESXi Authentication Bypass Vulnerability