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ESXi CVE-2020-3982

HIGH
Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367)
2020-10-20 security@vmware.com
7.7
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
Impact

CVSS score of 7.7 (HIGH). Attack characteristics: network attack vector, high complexity, high privileges required, no user interaction not required.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.8% exploitation probability (EPSS)

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AnalysisAI

VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202008101-SG, 6.5 before ESXi650-202007101-SG), Workstation (15.x), Fusion (11.x before 11.5.6) contain an out-of-bounds write. Rated high severity (CVSS 7.7), this vulnerability is remotely exploitable.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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 under CWE-367. VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202008101-SG, 6.5 before ESXi650-202007101-SG), Workstation (15.x), Fusion (11.x before 11.5.6) contain an out-of-bounds write vulnerability due to a time-of-check time-of-use issue in ACPI device. A malicious actor with administrative access to a virtual machine may be able to exploit this vulnerability to crash the virtual machine's vmx process or corrupt hypervisor's memory heap. Affected products include: Vmware Esxi, Vmware Cloud Foundation, Vmware Workstation, Vmware Workstation Player, Vmware Fusion. Version information: before 11.5.6.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.7 HIGH
AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202008101-SG, 6.5 before ESXi650-202007101-SG), Workstation (15.x), Fusion (11.x before 11.5.6) contain an out-of-bounds write vulnerability due to a time-of-check time-of-use issue in ACPI device. A malicious actor with administrative access to a virtual machine may be able to exploit this vulnerability to crash the virtual machine's vmx process or corrupt hypervisor's memory heap.

Threat Intelligence Overview

EPSS Score
0.8%
Top 47% exploitable
Data Quality
2 sources
Confidence: Low

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 HIGH
CISA KEV No
Public POC No
EPSS 0.8%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)NVD

cpe:2.3:o:vmware:esxi:7.0.0:-:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:7.0.0:1.20.16321839:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:-:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201806001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201807001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201808001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810103:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810201:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810202:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810203:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810204:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810205:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810206:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810207:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810208:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810209:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.7:670-201810210:*:*:*:*:*:*
+ 205 more

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