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Memory Buffer Bounds ErrorWeakness · CWE-119

CVE-2025-62623

HIGH · 8.8 CVSS v4.0 Published 2026-05-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
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
A heap-based buffer overflow in the ionic cloud driver for VMware ESXi could allow an attacker to achieve privilege escalation, potentially resulting in arbitrary code execution.

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 · moderate confidence

A heap-based buffer overflow vulnerability in the ionic cloud driver for VMware ESXi allows an attacker with local access to achieve privilege escalation, potentially executing arbitrary code with elevated privileges on the hypervisor.

MitigationApply the vendor-supplied VMware ESXi patch for CVE-2025-62623 and restart affected hosts as required. Restrict access to the ionic cloud driver interfaces to trusted administrative personnel only.

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
High
Privileges
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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. Confirm VMware ESXi is installed
    Run 'vmware -v' or check /etc/vmware/version to identify the hypervisor
    Affected if System is not VMware ESXi (this CVE only affects ESXi)
  2. Locate the ionic cloud driver
    Search for the ionic cloud driver module file: 'find / -name "*ionic*" 2>/dev/null' or check /usr/lib/vmware/ionic for driver components
    Affected if The ionic cloud driver component is not present on the system
  3. Verify ionic cloud driver is loaded
    Run 'esxcli system module list' to list loaded modules and look for ionic-related modules, or check 'vmware -l' for loaded drivers
    Affected if The ionic cloud driver is not loaded or active (exploit requires the driver to be running)
  4. Check ESXi version against vendor patch status
    Run 'vmware -v' to get the build number and version, then compare against VMware security advisories for CVE-2025-62623 patched versions
    Affected if The ESXi version/build predates the vendor patch for this CVE (version is vulnerable)
  5. Inspect driver configuration and access controls
    Review driver configuration files in /etc/vmware/ionic/ or check 'esxcli system module parameter list' for ionic driver parameters
    Affected if Driver is accessible without proper administrative access controls or has insecure configuration parameters

User is affected if running VMware ESXi with the ionic cloud driver loaded, where the ESXi version predates the vendor patch for CVE-2025-62623

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 the vendor-supplied VMware ESXi patch for CVE-2025-62623 and restart affected hosts as required. Restrict access to the ionic cloud driver interfaces to trusted administrative personnel only.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2025-62623 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