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Windows Server 2012Operating system · Microsoft

CVE-2025-27479

HIGH · 7.5 CVSS v3.1 Published 2025-04-08
Fix available
A fix is available. Upgrade to 10.0.14393.7969 / 10.0.17763.7136 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
Insufficient resource pool in Windows Kerberos allows an unauthorized attacker to deny service over a network.

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 Denial of Service vulnerability in Windows Kerberos caused by an insufficient resource pool. An unauthenticated remote attacker can send specially crafted network requests to the Kerberos service, potentially exhausting resources and causing the service to become unavailable.

MitigationApply the Microsoft security update for CVE-2025-27479 through Windows Update or your patch management system. Prioritize domain controllers and systems performing Kerberos authentication.

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 Server 2012Operating system
Affected:all versions= r2
Windows Server 2016Operating system
Affected:< 10.0.14393.7969
Windows Server 2019Operating system
Affected:< 10.0.17763.7136
Windows Server 2022Operating system
Affected:< 10.0.20348.3453
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.1551
Windows Server 2025Operating system
Affected:< 10.0.26100.3775

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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. Check Windows Server version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to display the Windows build number
    Affected if The build number falls below the fixed version for your Windows Server edition (e.g., < 10.0.14393.7969 for Server 2016, < 10.0.17763.7136 for Server 2019, < 10.0.20348.3453 for Server 2022, < 10.0.25398.1551 for Server 2022 23h2, < 10.0.26100.3775 for Server 2025, or any Server 2012/R2 version)
  2. Confirm the system is a Domain Controller or runs the KDC role
    Run 'Get-ADDomainController -Filter *' in PowerShell (if AD module is available) or check if the 'Key Distribution Center' service (kdsvc) exists and is running using 'Get-Service kdc'
    Affected if The Key Distribution Center service is present and running on the server, exposing the Kerberos service to network requests

The system is affected if it runs an unpatched Windows Server 2012/2012R2, 2016, 2019, 2022, 2022 23h2, or 2025 version below the specified build thresholds AND has the Kerberos KDC role enabled (typically domain controllers).

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
Upgrade available Upgrade to 10.0.14393.7969 / 10.0.17763.7136 / 10.0.20348.3453 or later
Fixed in 10.0.14393.796910.0.17763.713610.0.20348.3453
Interim mitigation

Apply the Microsoft security update for CVE-2025-27479 through Windows Update or your patch management system. Prioritize domain controllers and systems performing Kerberos authentication.

Recommended fix High confidence

Windows Server 2016: build 10.0.14393.7969 or later | Windows Server 2019: build 10.0.17763.7136 or later | Windows Server 2022: build 10.0.20348.3453 or later | Windows Server 2022 23h2: build 10.0.25398.1551 or later | Windows Server 2025: build 10.0.26100.3775 or later

  1. Identify the current Windows Server version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine the required build number for your Windows Server version from the affected versions list
  3. Apply the latest Windows Cumulative Update or Security Update from Microsoft Update Catalog
  4. Verify the update installed successfully by checking the build number matches or exceeds: Windows Server 2016: 10.0.14393.7969, Windows Server 2019: 10.0.17763.7136, Windows Server 2022: 10.0.20348.3453, Windows Server 2022 23h2: 10.0.25398.1551, Windows Server 2025: 10.0.26100.3775
  5. Restart the server as prompted to complete the update installation
  6. For Windows Server 2012/2012 R2: Plan migration to a supported Windows Server version as these releases are end-of-life and receive no security updates
Caveat Test updates in non-production environment before deployment; Windows Server 2012/2012 R2 has no patch available and requires migration to supported version

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

Fix this in Windows Server 2012 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2025-27479 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