CVE-2020-3967

Hypervisor code execution via unchecked EHCI copy

Published Jun 25, 2020 · Updated Aug 4, 2024

Heap overflow in the EHCI controller in VMware ESXi, Workstation, and Fusion allows guest OS users to execute code on the hypervisor. The EHCI component copies user-supplied data into a heap-based buffer without first validating the supplied length, allowing an overwrite. Exploitation requires local access to a virtual machine and additional conditions beyond attacker control; success escapes the guest context.

CVSS severity8.1
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in the EHCI controller in VMware ESXi, Workstation, and Fusion allows guest OS users to execute code on the hypervisor. The EHCI component copies user-supplied data into a heap-based buffer without first validating the supplied length, allowing an overwrite. Exploitation requires local access to a virtual machine and additional conditions beyond attacker control; success escapes the guest context.

The record

CVE
CVE-2020-3967
Published
Jun 25, 2020
Updated
Aug 4, 2024
Vendor
VMware
Product
VMware Workstation
Classifications
CWE-787, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.x before 15.5.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

VMware · VMware Workstationversion=15.x before 15.5.5
VMware · VMware Fusionversion=11.x before 11.5.5
VMware · VMware ESXiversion=6.5 before ESXi650-202005401-SG; version=6.7 before ESXi670-202004101-SG; version=7.0 before ESXi_7.0.0-1.20.16321839

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
8.1VMwareCVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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