Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2020-3992

OpenSLP as used in VMware ESXi has a... Remote Code Execution

VMware ESXi · VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG)

Watch CVE-2020-3992 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
83.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2020-3992 is an unauthenticated vulnerability affecting VMware ESXi. OpenSLP as used in VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG) has a...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

VMware ESXi vmware esxi (7.0 before esxi_7.0.1-0.0.16850804, 6.7 before esxi670-202010401-sg, 6.5 before esxi650-202010401-sg).

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

OpenSLP as used in VMware ESXi has a... Remote Code Execution

OpenSLP as used in VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG) has a use-after-free issue.

A malicious actor residing in the management network who has access to port 427 on an ESXi machine may be able to trigger a use-after-free in the OpenSLP service resulting in remote code execution.

n/a Affected
VMware ESXi
VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG)
Published
20 Oct 2020
Exploitation Reported
03 Nov 2021
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

malware cisa ransomware

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 03 Nov 2021

A trusted third party reported exploitation.

Used in malware

CISA

Recorded 03 Nov 2021

Malware families have been linked to exploitation of this CVE.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
CISA First 2021-11-03 00:00 UTC
CVE 2026-08-12 04:21 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

83.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Use After Free CWE-416

All CVSS Scores

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 10.0 High

AV:N/AC:L/Au:N/C:C/I:C/A:C

Timeline

From disclosure to observed exploitation

  1. 04:21 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  2. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 00:00 UTC

    First public exploitation report

    Exploit observed in malware

  4. 16:11 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2020-3992

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2020-3992",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.83015,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}