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CVE-2020-3992 VMware CVE debrief

CVE-2020-3992 is a VMware ESXi vulnerability in OpenSLP described by CISA as a use-after-free issue. It was added to the CISA Known Exploited Vulnerabilities catalog on 2021-11-03, indicating confirmed exploitation in the wild. CISA also marks it as having known ransomware campaign use, so ESXi environments should treat it as an urgent remediation item and follow VMware’s update guidance.

Vendor
VMware
Product
ESXi
CVSS
CRITICAL 9.8
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

VMware ESXi administrators, virtualization teams, infrastructure security teams, and incident responders responsible for internet-facing or business-critical ESXi hosts should prioritize this CVE.

Technical summary

The official record identifies the flaw as an OpenSLP use-after-free vulnerability in VMware ESXi. CISA’s KEV entry confirms active exploitation and notes known ransomware campaign use. The provided official guidance is to apply updates per vendor instructions; no exploit mechanics are included here.

Defensive priority

Urgent. This is a CISA KEV-listed vulnerability with known ransomware campaign use, so remediation should be prioritized ahead of routine patch cycles.

Recommended defensive actions

  • Apply VMware updates per vendor instructions as soon as possible.
  • Inventory ESXi hosts to confirm which systems are affected and whether they are exposed or high value.
  • Prioritize remediation of externally reachable or production ESXi systems.
  • Review security monitoring for signs of unauthorized access or suspicious activity on ESXi infrastructure.
  • Validate backup, recovery, and incident-response readiness for virtualization hosts.
  • Track the official VMware and CISA guidance for any additional remediation notes.

Evidence notes

This debrief is based on the CISA Known Exploited Vulnerabilities feed entry for CVE-2020-3992 and the official CVE/NVD records linked from that entry. The source metadata states: vendor VMware, product ESXi, vulnerability name ‘VMware ESXi OpenSLP Use-After-Free Vulnerability,’ dateAdded 2021-11-03, dueDate 2022-05-03, and knownRansomwareCampaignUse ‘Known.’

Sources and references

Verified primary and authoritative sources

  • CVE-2020-3992 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2020-3992

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2020-3992 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2020-3992

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.