CVE-2021-21994: VMware Cloud Foundation

Critical severity, CVSS 9.8. EPSS: 1.2% chance of exploitation in the next 30 days.

SFCB (Small Footprint CIM Broker) as used in ESXi has an authentication bypass vulnerability. A malicious actor with network access to port 5989 on ESXi may exploit this issue to bypass SFCB authentication by sending a specially crafted request.

Affected products

• VMware Cloud Foundation: from 3.0, before 3.10.2 (fixed in 3.10.2); from 4.0, before 4.3 (fixed in 4.3)
• VMware ESXi: version 6.5 only; version 6.7 only; version 7.0 only

Published 2021-07-13. Last modified 2026-06-17.