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Workstation ProApplication · VMware

CVE-2017-4933

HIGH · 8.8 CVSS v3.1 Published 2017-12-20
Fix available
A fix is available. Upgrade to 8.5.9 / 12.5.8 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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 (6.5 before ESXi650-201710401-BG), Workstation (12.x before 12.5.8), and Fusion (8.x before 8.5.9) contain a vulnerability that could allow an authenticated VNC session to cause a heap overflow via a specific set of VNC packets resulting in heap corruption. Successful exploitation of this issue could result in remote code execution in a virtual machine via the authenticated VNC session. Note: In order for exploitation to be possible in ESXi, VNC must be manually enabled in a virtual machine's .vmx configuration file. In addition, ESXi must be configured to allow VNC traffic through the built-in firewall.

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

VMware products contain a heap overflow vulnerability in the VNC server implementation. An authenticated VNC session can send specially crafted packets that cause heap corruption, leading to potential remote code execution within the virtual machine. The vulnerability requires VNC to be explicitly enabled in the VM configuration.

MitigationUpgrade affected VMware products to the specified versions (ESXi 6.5 to ESXi650-201710401-BG or later, Workstation to 12.5.8 or later, Fusion to 8.5.9 or later). If upgrades are not immediately feasible, disable VNC in virtual machine configurations and block VNC traffic at the firewall.

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
Workstation ProApplication
Affected:>= 12.0.0, < 12.5.8= 14.0= 14.1.0
EsxiOperating system
Affected:= 6.5
FusionApplication
Affected:>= 8.0.0, < 8.5.9

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
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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 VMware product and version
    Run 'vmware -v' on ESXi host, or check Help > About VMware Workstation/Fusion on the desktop application
    Affected if The installed version falls within 12.0.0-12.5.8, 14.0, or 14.1.0 for Workstation; 6.5 for ESXi; or 8.0.0-8.5.9 for Fusion
  2. Confirm product type
    Determine whether the system runs VMware Workstation Pro, VMware ESXi, or VMware Fusion based on the environment type (desktop virtualization vs. hypervisor)
    Affected if Any of the three affected products are in use
  3. Check if VNC is enabled in virtual machines
    For Workstation: open each VM, go to VM > Settings > Remote Display (VNC) and verify the 'Enable VNC connections' checkbox status. For ESXi: select each VM in vSphere Client, go to VM Options > Remote Console, check VNC settings. For Fusion: open each VM, go to VM > Settings > Remote Display, check VNC status
    Affected if VNC is explicitly enabled in any virtual machine configuration
  4. List all VMs with VNC ports exposed
    Review all virtual machine configuration files (.vmx for Workstation/Fusion, .vmx for ESXi) for lines containing 'RemoteDisplay.vnc.enabled' set to TRUE, or check via the respective management interface
    Affected if Any VM has RemoteDisplay.vnc.enabled = TRUE in its configuration

You are affected if you run any of the specified VMware product versions AND have VNC enabled in any virtual machine configuration, as the heap overflow only triggers when VNC is explicitly enabled.

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 8.5.9 / 12.5.8 or later
Fixed in 8.5.912.5.8
Interim mitigation

Upgrade affected VMware products to the specified versions (ESXi 6.5 to ESXi650-201710401-BG or later, Workstation to 12.5.8 or later, Fusion to 8.5.9 or later). If upgrades are not immediately feasible, disable VNC in virtual machine configurations and block VNC traffic at the firewall.

Fix this in Workstation Pro Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,180
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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-2017-4933 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