CVE-2021-21991

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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 local privilege escalation vulnerability due to the way it handles session tokens. A malicious actor with non-administrative user access on vCenter Server host may exploit this issue to escalate privileges to Administrator on the vSphere Client (HTML5) or vCenter Server vSphere Web Client (FLEX/Flash).

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

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