Cloud FoundationApplication · VMware
CVE-2020-3971
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 · uneditedVMware ESXi (6.7 before ESXi670-201904101-SG and 6.5 before ESXi650-201907101-SG), Workstation (15.x before 15.0.2), and Fusion (11.x before 11.0.2) contain a heap overflow vulnerability in the vmxnet3 virtual network adapter. A malicious actor with local access to a virtual machine with a vmxnet3 network adapter present may be able to read privileged information contained in physical memory.
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 confidenceHeap overflow vulnerability in VMware's vmxnet3 virtual network adapter allows a malicious actor with local access to a virtual machine to read privileged information contained in physical memory.
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
>= 3.0, < 3.7.2
FusionApplication
>= 11.0.0, < 11.0.2
WorkstationApplication
>= 15.0.0, < 15.0.2
EsxiOperating system
= 6.5= 6.7CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Identify the VMware product and versionOn the ESXi host, run 'vmware -v' or check the vSphere Client for the ESXi version. For Workstation, go to Help > About VMware Workstation. For Fusion, go to VMware Fusion > About VMware Fusion.Affected if The product is ESXi 6.5 or 6.7, Workstation 15.0.0-15.0.2, Fusion 11.0.0-11.0.2, or Cloud Foundation 3.0-3.7.1
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Locate virtual machines using vmxnet3 adapterFor ESXi, use 'esxcli network vm list' to list VMs, then check VMX configuration files for 'ethernetX.virtualDev = vmxnet3'. For Workstation/Fusion, open VM settings and inspect each network adapter.Affected if Any virtual machine is configured with a vmxnet3 virtual network adapter
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Verify the guest has local access to the VMReview VM access controls and determine if an untrusted user or process can execute code within the guest virtual machine.Affected if An untrusted actor can execute code inside a guest VM on an affected VMware platform with vmxnet3 configured
You are affected if you run any of the listed unpatched VMware products with a vmxnet3 adapter configured in a guest VM where an untrusted user has local access.
Generated from the published advisory. Verify against your own configuration.
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 data3.7.211.0.215.0.2
Apply vendor patches: ESXi 6.7 update to ESXi670-201904101-SG or later, ESXi 6.5 update to ESXi650-201907101-SG or later, VMware Workstation to 15.0.2 or later, and Fusion to 11.0.2 or later.
Fix this in Cloud Foundation
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3971 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3971 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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