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Use of Uninitialized ResourceWeakness · CWE-908

CVE-2025-41239

HIGH · 7.1 CVSS v3.1 Published 2025-07-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
76/100
Remediation priority · High
No privileges 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, Workstation, Fusion, and VMware Tools contains an information disclosure vulnerability due to the usage of an uninitialised memory in vSockets. A malicious actor with local administrative privileges on a virtual machine may be able to exploit this issue to leak memory from processes communicating with vSockets.

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 ESXi, Workstation, Fusion, and VMware Tools contain an information disclosure vulnerability stemming from the use of uninitialized memory in the vSockets virtual device. An attacker with local administrative privileges on a guest virtual machine can exploit this issue to read memory contents from other processes that communicate through vSockets, potentially exposing sensitive data.

MitigationApply VMware security patches when available. Until then, limit administrative access to virtual machines and monitor for unusual memory access patterns from guest systems.

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

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
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/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 checks

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

  1. Identify installed VMware product
    Determine if the system runs ESXi, Workstation, Fusion, or VMware Tools. On ESXi, use 'vmware -v' or check the vSphere Client. On Workstation/Fusion, check Help > About. For VMware Tools, check the guest OS package or installer version.
    Affected if The product is ESXi, Workstation, Fusion, or VMware Tools and the version falls within the affected range.
  2. Compare installed version to affected releases
    Match your identified product version against the VMware security advisories for CVE-2025-41239. VMware typically publishes these in VMSA (VMware Security Advisories) with specific version numbers.
    Affected if The installed version is lower than the patched version listed in VMware advisories.
  3. Check for vSockets virtual device presence
    Examine VM configuration files (.vmx for Workstation/Fusion, .vmx or via vSphere for ESXi) for entries containing 'v socket', 'vsocket', or 'vmci' related to AF_VSOCK. On ESXi, use 'vim-cmd vmsvc/getallvms' and inspect the VMX or use the vSphere Client to view virtual device list.
    Affected if The VM configuration includes a vSockets (VSOCK) virtual device and the VMware product version is unpatched.
  4. Verify processes using vSockets communication
    On the ESXi host, run 'esxcli network socket list' or inspect VM processes for AF_VSOCK connections. In guest VMs, use 'ss -l' or 'netstat' to listen on VSOCK ports. Check for services using vsock protocol.
    Affected if Any VM on the host has processes communicating via vSockets, increasing the attack surface for information disclosure.
  5. Audit guest VM administrative access
    Review which users have administrative or root privileges inside guest VMs. On ESXi, use the vSphere Client or PowerCLI to list VM users and permissions. Check for unauthorized local admin accounts in guest operating systems.
    Affected if Guest VMs with vSockets enabled also have local administrative users, creating the conditions required for the exploit.

The environment is affected if an unpatched version of ESXi, Workstation, Fusion, or VMware Tools is running with vSockets virtual devices enabled on VMs that have guest administrative users.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply VMware security patches when available. Until then, limit administrative access to virtual machines and monitor for unusual memory access patterns from guest systems.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
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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-2025-41239 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
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