dbcve.org
Windows 10 1809Operating system · Microsoft

CVE-2026-27918

HIGH · 7.0 CVSS v3.1 Published 2026-04-14
Fix available
A fix is available. Upgrade to 10.0.17763.8644 / 10.0.19044.7184 or later.
See remediation →
72/100
Remediation priority · Elevated
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
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Shell 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 · moderate confidence

A race condition vulnerability exists in Windows Shell where concurrent access to a shared resource lacks proper synchronization. An authorized local attacker can exploit this timing vulnerability to elevate their privileges to a higher integrity level, potentially achieving administrator or SYSTEM privileges.

MitigationApply Microsoft security updates for Windows Shell when available. Until a patch is released, monitor for suspicious processes and limit local user privileges. Audit system for indicators of compromise related to privilege escalation attempts.

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:< 10.0.17763.8644
Windows 10 21h2Operating system
Affected:< 10.0.19044.7184
Windows 10 22h2Operating system
Affected:< 10.0.19045.7184
Windows 11 23h2Operating system
Affected:< 10.0.22631.6936
Windows 11 24h2Operating system
Affected:< 10.0.26100.8246
Windows 11 25h2Operating system
Affected:< 10.0.26200.8246
Windows 11 26h1Operating system
Affected:< 10.0.28000.1836
Windows Server 2019Operating system
Affected:< 10.0.17763.8644

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
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/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. Retrieve Windows build number
    Run 'winver' from command prompt or 'systeminfo' and locate the 'OS Build' or 'Build' line
    Affected if The build number is lower than the fixed version for your Windows release (10.0.17763.8644 for 1809/Server 2019, 10.0.19044.7184 for 21h2, 10.0.19045.7184 for 22h2, 10.0.22631.6936 for 23h2, 10.0.26100.8246 for 24h2, 10.0.26200.8246 for 25h2, 10.0.28000.1836 for 26h1)
  2. Identify Windows release version
    Run 'winver' or check 'systeminfo' to determine if you are on Windows 10 1809, 21h2, 22h2, Windows 11 23h2, 24h2, 25h2, 26h1, or Windows Server 2019
    Affected if Your Windows release matches one listed in the affected versions and the build is below the corresponding threshold
  3. Confirm Shell component version
    Check the Windows Shell version by inspecting the file properties of %SystemRoot%\System32\shell32.dll or using 'powershell Get-ItemProperty -Path "C:\Windows\System32\shell32.dll" | Select-Object VersionInfo'
    Affected if The shell32.dll version corresponds to a build below the fixed version for your Windows release

You are affected if your Windows build number is lower than the fixed build for your specific Windows release (1809/2019, 21h2, 22h2, 23h2, 24h2, 25h2, or 26h1) as listed in the affected versions.

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 10.0.17763.8644 / 10.0.19044.7184 / 10.0.19045.7184 or later
Fixed in 10.0.17763.864410.0.19044.718410.0.19045.7184
Interim mitigation

Apply Microsoft security updates for Windows Shell when available. Until a patch is released, monitor for suspicious processes and limit local user privileges. Audit system for indicators of compromise related to privilege escalation attempts.

Recommended fix High confidence

Windows 10 1809: build 10.0.17763.8644 or later | Windows 10 21h2: build 10.0.19044.7184 or later | Windows 10 22h2: build 10.0.19045.7184 or later | Windows 11 23h2: build 10.0.22631.6936 or later | Windows 11 24h2: build 10.0.26100.8246 or later | Windows 11 25h2: build 10.0.26200.8246 or later |

  1. Open Settings > Update & Security > Windows Update
  2. Click 'Check for updates' to fetch the latest available updates
  3. Review the available updates and ensure the cumulative security update for this CVE is listed
  4. Click 'Download and install' to apply the updates
  5. Restart the system when prompted to complete the installation
  6. After restart, verify the installation was successful by checking the OS build number in Settings > System > About
Caveat Standard Windows update applies; no special configuration changes required

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
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

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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-2026-27918 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