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ESXi CVE-2020-3992

CRITICAL
Use After Free (CWE-416)
2020-10-20 security@vmware.com
9.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could access freed memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: In CISA KEV with patch available.
Exploited in the wild (CISA KEV) Patch available 83.0% exploitation probability (EPSS)

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AnalysisAI

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. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. 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. Affected products include: Vmware Cloud Foundation, Vmware Esxi.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Added to CISA KEV
Jul 14, 2026 - 04:22 CISA
CVE Published
Oct 20, 2020 - 17:15 nvd
CRITICAL 9.8

DescriptionNVD

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.

Threat Intelligence Overview

Threat Score
7.5/10
Composite threat intelligence
EPSS Score
83.0%
Top 0% exploitable
Exploit
POC
Public exploit code exists
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV Yes
Public POC Yes
EPSS 83.0%
Patch available Yes
Active threat Yes
Deciding rule
In CISA KEV with patch available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Immediate
Exploitation· derived
Active
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
High

Priority Score

202
Low Medium High Critical
KEV: +50
EPSS: +83
CVSS: +49
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:-:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:2:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201701001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201703001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201703002:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201704001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707103:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707201:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707202:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707203:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707204:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707205:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707206:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707207:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707208:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707209:*:*:*:*:*:*
+ 204 more

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