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Vulnerability record · CVE-2021-21986 · published 26 May 2021

CVE-2021-21986: Vmware vcenter server missing authentication for critical function vulnerability

Vmware · Vcenter Server

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.

9.8 CVSS 3.1 Critical EPSS 13% · top 3.8% CWE-306 · Missing authentication for critical function
9.8CVSS 3.1 base score, v2 10.0
13%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html Third Party AdvisoryVDB Entry
https://www.vmware.com/security/advisories/VMSA-2021-0010.html Vendor Advisory
http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html Third Party AdvisoryVDB Entry
https://www.vmware.com/security/advisories/VMSA-2021-0010.html Vendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-21986), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.