The vSphere Client (HTML5) contains a vulnerability in a vSphere authentication mechanism for the Virtual SAN Health Check, Site Recovery,…

published 2021-05-26 5y ago modified 2026-06-17 4mo ago also EUVD-2021-9157

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 13.3%; EPSS 13.3% chance of exploitation in 30 days, percentile 96%
public exploits: 0; none known

The vSphere Client (HTML5) contains a vulnerability in a vSphere authentication mechanism for the Virtual SAN Health Check, Site Recovery, vSphere Lifecycle Manager, and VMware Cloud Director Availability plug-ins. A malicious actor with network access to port 443 on vCenter Server may perform actions allowed by the impacted plug-ins without authentication.

Patch / fix

fixed in 1

vmware cloud_foundation 3.10.2.1, 4.2.1

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Exploit prediction

13.27% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	10.0	AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

n/a VMware vCenter Server and VMware Cloud Foundation

Classification

Weakness

CWE-306 Missing Authentication for Critical Functionality

Technology feeds

VMware rss critical rss

References

vmware.com /security/advisories/VMSA-2021-0010.html
vendor-advisory
packetstormsecurity.com /files/162812/VMware-Security-Advisory-2021-0010.html
third-party-advisory, vdb-entry

Sources

CVE List CVE-2021-21986
NVD CVE-2021-21986

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