CVE-2021-21994
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...
- Published
- Jul 13, 2021
- Updated
- Aug 3, 2024
- Assigning CNA
- vmware
- Evidence observed
- Aug 15, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLow · next 30 days
- Percentile
- 65.2%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
1- cve-2021-21994_POCExploit
Validates and exploits VMware ESXi SFCB authentication bypass (CVE-2021-21994) via a probe/fuzz harness, enabling unauthenticated CIM-XML enumeration.
Responsible use
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