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Windows Server 2012Operating system · Microsoft

CVE-2026-41089

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 10.0.14393.9140 / 10.0.17763.8755 or later.
See remediation →
100/100
Remediation priority · Urgent
High EPSS 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
Stack-based buffer overflow in Windows Netlogon allows an unauthorized attacker to execute code 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 · high confidence

A stack-based buffer overflow vulnerability in Windows Netlogon service allows an unauthenticated remote attacker to execute arbitrary code on affected Windows systems. The flaw exists in the Netlogon RPC interface used for domain controller authentication and communication.

MitigationApply the relevant Microsoft security update for Windows Netlogon immediately. Restrict Netlogon RPC exposure to internal networks and disable NTLM authentication where possible to reduce attack surface.

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:< 10.0.14393.9140
Windows Server 2019Operating system
Affected:< 10.0.17763.8755
Windows Server 2022Operating system
Affected:< 10.0.20348.5074
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.2330
Windows Server 2025Operating system
Affected:< 10.0.26100.32772

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Check Windows Server version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the installed Windows Server version
    Affected if The version falls within the affected ranges: Server 2012 (all versions), 2016 < 10.0.14393.9140, 2019 < 10.0.17763.8755, 2022 < 10.0.20348.5074, 2022 23h2 < 10.0.25398.2330, or 2025 < 10.0.26100.32772
  2. Verify Netlogon service status
    Run 'Get-Service -Name Netlogon' in PowerShell or check Services.msc for the Netlogon service
    Affected if The Netlogon service is running or set to start automatically (vulnerability only applies if Netlogon is enabled)
  3. Check Netlogon RPC listener configuration
    Run 'netsh rpc show all' or use 'netstat -an | findstr "135 445"' to check if RPC endpoints are listening
    Affected if Netlogon RPC interfaces are exposed on network listeners (the flaw is in the Netlogon RPC interface)
  4. Determine if system is a domain controller
    Run 'Get-ADDomain' (if AD DS is installed) or check System Properties for 'Domain:' designation
    Affected if The server is a domain controller, as Netlogon is primarily used for DC authentication and communication

You are affected if your Windows Server version is within the affected ranges AND the Netlogon service is running and exposed via RPC on the network.

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 10.0.14393.9140 / 10.0.17763.8755 / 10.0.20348.5074 or later
Fixed in 10.0.14393.914010.0.17763.875510.0.20348.5074
Interim mitigation

Apply the relevant Microsoft security update for Windows Netlogon immediately. Restrict Netlogon RPC exposure to internal networks and disable NTLM authentication where possible to reduce attack surface.

Recommended fix High confidence

Windows Server 2016 build 10.0.14393.9140+ | Windows Server 2019 build 10.0.17763.8755+ | Windows Server 2022 build 10.0.20348.5074+ | Windows Server 2022 23h2 build 10.0.25398.2330+ | Windows Server 2025 build 10.0.26100.32772+

  1. Identify the current Windows Server version by running 'winver' or 'systeminfo'
  2. For Windows Server 2016: Upgrade to build 10.0.14393.9140 or later
  3. For Windows Server 2019: Upgrade to build 10.0.17763.8755 or later
  4. For Windows Server 2022: Upgrade to build 10.0.20348.5074 or later
  5. For Windows Server 2022 23h2: Upgrade to build 10.0.25398.2330 or later
  6. For Windows Server 2025: Upgrade to build 10.0.26100.32772 or later
  7. For Windows Server 2012/2012 R2: These versions are end-of-support and do not receive security updates; migrate to a supported Windows Server version
  8. Apply the upgrade via Windows Update, WSUS, or download the latest ISO from Microsoft Volume Licensing Service Center
Caveat Windows Server 2012/2012 R2 have no patch available and require migration to newer version; older application compatibility should be tested before upgrading production systems

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

Fix this in Windows Server 2012 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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Scan for this in your stack

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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-2026-41089 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