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Cloud FoundationApplication · VMware

CVE-2020-3968

HIGH · 8.2 CVSS v3.1 Published 2020-06-25
Fix available
A fix is available. Upgrade to 3.10 / 4.0.1 or later.
See remediation →
84/100
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 15.5.5), and Fusion (11.x before 11.5.5) contain an out-of-bounds write vulnerability in the USB 3.0 controller (xHCI). A malicious actor with local administrative privileges on a virtual machine may be able to exploit this issue to crash the virtual machine's vmx process leading to a denial of service condition or 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

Out-of-bounds write vulnerability in the xHCI USB 3.0 controller affecting VMware ESXi, Workstation, and Fusion. A malicious actor with local administrative privileges on a virtual machine can exploit this to crash the VM's vmx process (DoS) or potentially execute code on the hypervisor from within the guest VM.

MitigationApply vendor-supplied patches: ESXi 7.0 update to ESXi_7.0.0-1.20.16321839 or later, ESXi 670-202004101-SG or later, ESXi650-202005401-SG or later; Workstation to 15.5.5 or later; Fusion to 11.5.5 or later. Restrict VM administrative privileges where possible.

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, < 11.5.5
WorkstationApplication
Affected:>= 15.0.0, < 15.5.5
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
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/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 and version
    Run 'vmware -v' on the ESXi host (via SSH or console) or check Help > About in Workstation/Fusion. For ESXi, also check the ESXi welcome screen or Host Client summary view.
    Affected if The installed version falls within the affected ranges: ESXi 6.5, 6.7, or 7.0.0; Workstation 15.0.0 to <15.5.5; Fusion 11.0.0 to <11.5.5; Cloud Foundation 3.0 to <3.10 or 4.0.0 to <4.0.1
  2. Locate VM configuration files
    Browse to the VM's datastore directory and locate the .vmx file for each virtual machine. This file contains the virtual hardware configuration.
    Affected if The .vmx file exists and the VM is stored on the affected VMware platform.
  3. Check for xHCI USB controller in VM configuration
    Open the VM's .vmx file and search for lines containing 'xhci' or 'usb.xhci' configuration entries, such as 'usb.xhci.present = TRUE' or similar USB 3.0 controller settings.
    Affected if An xHCI USB 3.0 controller is configured and present in the VM (usb.xhci.present = TRUE or equivalent entry exists)
  4. Verify exploit prerequisites
    Confirm the VM has an xHCI USB controller attached and that untrusted users have administrative privileges inside the guest VM. This can be checked by reviewing VM permission settings and guest OS user accounts.
    Affected if The VM has an active xHCI USB controller AND the guest VM allows local administrative access to untrusted actors, providing the attack surface for exploitation

You are affected if your VMware product version matches one of the affected ranges AND any VM on that host has an xHCI USB 3.0 controller configured, because the vulnerability requires the xHCI controller to be present for exploitation.

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 / 11.5.5 or later
Fixed in 3.104.0.111.5.5
Interim mitigation

Apply vendor-supplied patches: ESXi 7.0 update to ESXi_7.0.0-1.20.16321839 or later, ESXi 670-202004101-SG or later, ESXi650-202005401-SG or later; Workstation to 15.5.5 or later; Fusion to 11.5.5 or later. Restrict VM administrative privileges where possible.

Fix this in Cloud Foundation Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get the upgrade done

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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-2020-3968 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