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Cloud FoundationApplication · VMware

CVE-2020-3966

HIGH · 7.5 CVSS v3.1 Published 2020-06-25
Fix available
A fix is available. Upgrade to 3.10 / 4.0.1 or later.
See remediation →
77/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
VMware ESXi (7.0 before ESXi_7.0.0-1.20.16321839, 6.7 before ESXi670-202004101-SG and 6.5 before ESXi650-202005401-SG), Workstation (15.x before 15.5.2), and Fusion (11.x before 11.5.2) contain a heap-overflow due to a race condition issue in the USB 2.0 controller (EHCI). A malicious actor with local access to a virtual machine may be able to exploit this vulnerability to execute code on the hypervisor from a virtual machine. Additional conditions beyond the attacker's control must be present for exploitation to be possible.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Heap-overflow vulnerability in the EHCI USB 2.0 controller of VMware hypervisors (ESXi, Workstation, Fusion) caused by a race condition. Allows a malicious actor with local VM access to execute code on the hypervisor, achieving VM escape.

MitigationUpdate VMware products to patched versions: ESXi 7.0.0-1.20.16321839 or later, ESXi670-202004101-SG or later, ESXi650-202005401-SG or later; Workstation 15.5.2 or later; Fusion 11.5.2 or later.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Cloud FoundationApplication
Affected:>= 3.0, < 3.10>= 4.0.0, < 4.0.1
FusionApplication
Affected:>= 11.0.0, < 11.5.2
WorkstationApplication
Affected:>= 15.0.0, < 15.5.2
EsxiOperating system
Affected:= 6.5= 6.7= 7.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the VMware product installed
    Run 'vmware -v' from command line, or check the application/host details in the VMware hypervisor interface (vSphere Client for ESXi, VMware Fusion/Workstation About dialog)
    Affected if The system is running ESXi, Workstation, or Fusion
  2. Determine the installed version of VMware ESXi
    On ESXi host, run 'vmware -v' via SSH/console, or check in vSphere Client under Host > Summary > General Information > Version
    Affected if Version equals 6.5, 6.7, or 7.0.0 exactly (these are the affected versions)
  3. Determine the installed version of VMware Workstation
    Run 'vmware -v' from command line, or check Help > About VMware Workstation
    Affected if Version is 15.0.0 or higher but lower than 15.5.2
  4. Determine the installed version of VMware Fusion
    Run 'vmware -v' from command line, or check VMware Fusion menu > About VMware Fusion
    Affected if Version is 11.0.0 or higher but lower than 11.5.2
  5. Check if any VM has USB 2.0 (EHCI) controller attached
    For Workstation/Fusion: open VM settings, look under USB Controller - verify if controller type shows 'USB 2.0' or 'EHCI'. For ESXi: edit VM settings > USB Controller and check Compatibility setting
    Affected if A USB 2.0/EHCI controller is configured and attached to any virtual machine on the host

User is affected if they run affected VMware product versions AND have a VM with USB 2.0 (EHCI) controller enabled, as the vulnerability requires the EHCI USB controller to be present to trigger the heap-overflow.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 3.10 / 4.0.1 / 11.5.2 or later
Fixed in 3.104.0.111.5.2
Interim mitigation

Update VMware products to patched versions: ESXi 7.0.0-1.20.16321839 or later, ESXi670-202004101-SG or later, ESXi650-202005401-SG or later; Workstation 15.5.2 or later; Fusion 11.5.2 or later.

Fix this in Cloud Foundation Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-3966 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data