Windows ServerOperating system · Microsoft

CVE-2022-21910

HIGH · 7.8 CVSS v3.1 Published 2022-01-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
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
Microsoft Cluster Port Driver Elevation of Privilege Vulnerability

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

This is a local Elevation of Privilege vulnerability in the Microsoft Cluster Port Driver (clusport.sys), a kernel-mode driver used by Windows Failover Clustering. The vulnerability allows a local attacker to escalate privileges to kernel/system level.

MitigationApply Microsoft security updates for CVE-2022-21910. As this is a local privilege escalation, prioritize patching systems with Windows Failover Clustering enabled, particularly domain controllers and critical infrastructure servers.

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
Windows ServerOperating system
Affected:= 20h2= 2022
Windows Server 2016Operating system
Affected:all versions
Windows Server 2019Operating system
Affected:all versions

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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 Windows Server version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the installed Windows Server version
    Affected if Version matches 20h2, 2022, Server 2016, or Server 2019
  2. Check if clusport.sys driver is loaded
    Run 'driverquery /v | findstr clusport' or check in Device Manager under 'Microsoft Cluster Port Driver' to see if the driver is loaded
    Affected if The clusport.sys driver is present and loaded in memory
  3. Verify Windows Failover Clustering feature status
    Run 'Get-WindowsFeature Failover-Clustering' in PowerShell or check via Server Manager to see if the Failover Clustering role is installed
    Affected if Failover Clustering feature is installed and the clusport.sys driver is in use

A system is affected if it runs a vulnerable Windows Server version (20h2, 2022, 2016, or 2019) AND has the clusport.sys driver loaded (typically when Failover Clustering is 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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft security updates for CVE-2022-21910. As this is a local privilege escalation, prioritize patching systems with Windows Failover Clustering enabled, particularly domain controllers and critical infrastructure servers.

Recommended fix High confidence

Install the January 2022 Security Monthly Quality Rollup or the specific KB update (KB5009557 for 2022, KB5009555 for 2019, KB5009566 for 2016, KB5009535 for 20H2)

  1. Identify your Windows Server version (Server 2016, 2019, 20H2, or 2022)
  2. Open Windows Update or check Microsoft Update Catalog
  3. Install the January 2022 Security Update corresponding to your OS version: For Windows Server 2022 install KB5009557, for Windows Server 2019 install KB5009555, for Windows Server 2016 install KB5009566, for Windows Server version 20H2 install KB5009535
  4. Restart the server after installing the update
  5. Verify the update is installed by checking installed updates or running: Get-HotFix | Where-Object {$_.HotFixID -eq 'KB5009557' -or $_.HotFixID -eq 'KB5009555' -or $_.HotFixID -eq 'KB5009566' -or $_.HotFixID -eq 'KB5009535'}
Caveat Standard patching risk - test in non-production environment first; may require restart

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-21910 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-21910 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