CVE-2021-21985

CVE-2021-21985 is a critical-severity vulnerability in Vmware Vcenter Server with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-918.

Key facts

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-21985?
CVE-2021-21985 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21985 being actively exploited?
Yes. CVE-2021-21985 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-21985?
CVE-2021-21985 primarily affects Vmware Vcenter Server. In total, 52 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21985?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-21985 have an EU (EUVD) identifier?
Yes. CVE-2021-21985 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-9156. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2021-21985 published?
CVE-2021-21985 was published on 2021-05-26 and last updated on 2026-08-12.

References

Affected products (52)

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