CVE-2021-21992

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-22 · updated 2026-06-17

Description

The vCenter Server contains a denial-of-service vulnerability due to improper XML entity parsing. A malicious actor with non-administrative user access to the vCenter Server vSphere Client (HTML5) or vCenter Server vSphere Web Client (FLEX/Flash) may exploit this issue to create a denial-of-service condition on the vCenter Server host.

Affected products

VMware Cloud Foundation: from 3.0 before 3.10.2.2; from 4.0 before 4.3 — fixed in 3.10.2.2, 4.3
VMware vCenter Server: 6.5, 6.5-a, 6.5-b, 6.5-c, 6.5-d, 6.5-e (+48)
VMware vCenter Server, VMware Cloud Foundation: VMware vCenter Server(7.x before 7.0 U2c, 6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation (4.x before 4.3 and 3.x before 3.10.2.2)

How to fix

Upgrade to a fixed version: VMware Cloud Foundation 3.10.2.2, 4.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2021-21992 or the next vulnerability affects your stack