Exploited vulnerability · CISA KEV

Is CVE-2020-3992 exploited? Yes: in CISA KEV since 3 Nov 2021

Gociux · VMware ESXi · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2020-3992, VMware ESXi OpenSLP Use-After-Free Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, 379 days after it was published. It is known to be used in ransomware campaigns. It affects VMware ESXi. If you run it, CISA's required action is: Apply updates per vendor instructions.

What it is

VMware ESXi OpenSLP contains a use-after-free vulnerability that allows an attacker residing in the management network with access to port 427 to perform remote code execution.

What to do

1. Check whether you run it. Look for ESXi in your asset inventory, including appliances and cloud images. Stack check lists every exploited VMware CVE at once.
2. Apply the fix. Apply updates per vendor instructions.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 20 Oct 2020.
4. Get told next time. Email alerts when CISA adds a CVE for VMware.

Other exploited CVEs in ESXi

• CVE-2025-22225: VMware ESXi Arbitrary Write Vulnerability (4 Mar 2025)
• CVE-2024-37085: VMware ESXi Authentication Bypass Vulnerability (30 Jul 2024)

References

• nvd.nist.gov/vuln/detail/CVE-2020-3992

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in November 2021 · VMware scorecard · act-now radar.