CVE-2020-3964Public exploit

Hypervisor-memory disclosure via unchecked qTD read

Published Jun 25, 2020 · Updated Aug 4, 2024

Information disclosure in VMware ESXi, Workstation 15.x, and Fusion 11.x allows guest OS users to read hypervisor memory through EHCI. EhciReadTDBuffer ignores a failed ReadBytes result, leaving a heap-allocated URB buffer uninitialized before its contents are sent to a USB device. Exploitation requires local virtual-machine access, a guest-controlled invalid qTD address, an attached USB device, and additional conditions outside the attacker's control.

CVSS severity5.9
Medium
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

Information disclosure in VMware ESXi, Workstation 15.x, and Fusion 11.x allows guest OS users to read hypervisor memory through EHCI. EhciReadTDBuffer ignores a failed ReadBytes result, leaving a heap-allocated URB buffer uninitialized before its contents are sent to a USB device. Exploitation requires local virtual-machine access, a guest-controlled invalid qTD address, an attached USB device, and additional conditions outside the attacker's control.

The record

CVE
CVE-2020-3964
Published
Jun 25, 2020
Updated
Aug 4, 2024
Vendor
VMware
Product
VMware Workstation
Classifications
CWE-908, T1005
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 15.5.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

VMware · VMware Workstationversion=15.x before 15.5.2
VMware · VMware Fusionversion=11.x before 11.5.2
VMware · VMware ESXiversion=6.5 before ESXi650-202005401-SG; version=6.7 before ESXi670-202006401-SG; version=7.0 before ESXi_7.0.0-1.20.16321839

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
5.9VMwareCVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1005Data from Local System

Public exploit references

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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