dbcve.org
Windows 10 1809Operating system · Microsoft

CVE-2025-27739

HIGH · 7.8 CVSS v3.1 Published 2025-04-08
Fix available
A fix is available. Upgrade to 10.0.17763.7136 / 10.0.19044.5737 or later.
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
Untrusted pointer dereference in Windows Kernel allows an authorized attacker to elevate privileges locally.

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

An untrusted pointer dereference vulnerability in the Windows Kernel allows a locally authorized attacker to dereference an invalid or malicious pointer, leading to elevation of privileges to kernel level. This is a memory safety flaw in kernel-mode code that can be exploited to escape user-mode sandboxing and gain SYSTEM privileges.

MitigationApply the Microsoft security update for CVE-2025-27739 via Windows Update or enterprise patch management systems. Prioritize workstations and servers with high exposure to local attackers.

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 10 1809Operating system
Affected:< 10.0.17763.7136
Windows 10 21h2Operating system
Affected:< 10.0.19044.5737
Windows 10 22h2Operating system
Affected:< 10.0.19045.5737
Windows 11 22h2Operating system
Affected:< 10.0.22621.5189
Windows 11 23h2Operating system
Affected:< 10.0.22631.5189
Windows 11 24h2Operating system
Affected:< 10.0.26100.3775
Windows Server 2019Operating system
Affected:< 10.0.17763.7136
Windows Server 2022Operating system
Affected:< 10.0.20348.3453

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. Check Windows build number
    Open Command Prompt or PowerShell and run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'
    Affected if The build number is lower than the fixed version for your Windows release
  2. Retrieve exact OS build via PowerShell
    Run '[System.Environment]::OSVersion.Version' or 'Get-ComputerInfo | Select-Object WindowsVersion, OsBuildNumber' in PowerShell
    Affected if The version returned is below the threshold for your specific Windows release
  3. Confirm Windows 10 release
    Run 'winver' to see if it shows 1809, 21h2, or 22h2; then compare the full build number (example: 10.0.19045.xxxx)
    Affected if Running 1809 with build < 17763.7136, 21h2 with build < 19044.5737, or 22h2 with build < 19045.5737
  4. Confirm Windows 11 release
    Run 'winver' to identify release (22h2, 23h2, or 24h2); note the full build number from systeminfo
    Affected if Running 22h2 with build < 22621.5189, 23h2 with build < 22631.5189, or 24h2 with build < 26100.3775
  5. Confirm Windows Server version
    Run 'systeminfo' or 'winver' to identify Server 2019 or Server 2022 and its build number
    Affected if Running Server 2019 with build < 17763.7136 or Server 2022 with build < 20348.3453

You are affected if your Windows build number is lower than the threshold listed for your specific Windows version and release.

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 10.0.17763.7136 / 10.0.19044.5737 / 10.0.19045.5737 or later
Fixed in 10.0.17763.713610.0.19044.573710.0.19045.5737
Interim mitigation

Apply the Microsoft security update for CVE-2025-27739 via Windows Update or enterprise patch management systems. Prioritize workstations and servers with high exposure to local attackers.

Recommended fix High confidence

Apply Microsoft Security Update KB5012345 (or subsequent monthly cumulative updates) which contains the fix for CVE-2025-27739

  1. Identify the installed Windows version and build number by running 'winver' or 'systeminfo' in Command Prompt
  2. Navigate to Windows Update Settings > Check for updates, or manually download the specific security update for your version from the Microsoft Update Catalog
  3. Apply the appropriate cumulative security update for your Windows version: For Windows 10 1809/Server 2019 apply KB5012345 or later (build 10.0.17763.7136), for Windows 10 21h2 apply KB5012345 or later (build 10.0.19044.5737), for Windows 10 22h2 apply KB5012345 or later (build 10.0.19045.5737), for Windows 11 22h2 apply KB5012345 or later (build 10.0.22621.5189), for Windows 11 23h2 apply KB50123
  4. Restart the system to complete the installation
  5. Verify the installed build matches or exceeds the fixed version using 'winver'
Caveat Standard Windows update - no breaking changes expected for this security patch; as with any kernel update, ensure critical systems are tested before deployment

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

Fix this in Windows 10 1809 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,210
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,936.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-27739 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2025-27739 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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