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Windows 10 1809Operating system · Microsoft

CVE-2026-42978

HIGH · 7.8 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 10.0.17763.8880 / 10.0.19044.7417 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
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Push Notifications 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

This is a race condition vulnerability in Windows Push Notifications where improper synchronization of shared resources allows a locally authorized attacker to execute code with elevated privileges. The vulnerability stems from concurrent access to a shared resource without proper locking mechanisms.

MitigationApply the applicable Windows security update once released by Microsoft to address the race condition in Push Notifications. Since this is a local privilege escalation, ensure attackers already on the system have limited initial access through proper least-privilege configurations.

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:< 10.0.17763.8880
Windows 10 21h2Operating system
Affected:< 10.0.19044.7417
Windows 10 22h2Operating system
Affected:< 10.0.19045.7417
Windows 11 23h2Operating system
Affected:< 10.0.22631.7219
Windows 11 24h2Operating system
Affected:< 10.0.26100.8655
Windows 11 25h2Operating system
Affected:< 10.0.26200.8655
Windows 11 26h1Operating system
Affected:< 10.0.28000.2269
Windows Server 2019Operating system
Affected:< 10.0.17763.8880

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/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 version
    Run 'winver' or 'systeminfo' and note the OS Build number (for example, 10.0.17763.xxxx)
    Affected if The installed build number is lower than any of these thresholds: 17763.8880, 19044.7417, 19045.7417, 22631.7219, 26100.8655, 26200.8655, 28000.2269
  2. Identify exact Windows release
    Run 'winver' to identify the specific release (such as Windows 10 1809, Windows 11 23h2, Windows Server 2019)
    Affected if The identified release matches one in the affected list AND its version is below the corresponding threshold
  3. Verify Push Notifications service status
    Check the Windows Push Notification service via Services.msc or run 'Get-Service WpnService' in PowerShell
    Affected if The Windows Push Notification Service (WpnUserService) is running or set to Automatic start
  4. Check if notifications are user-configured
    Inspect registry at HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Notifications\Settings for Enabled value, or check Settings > System > Notifications
    Affected if User notifications are enabled (setting value is 1)

The system is affected if it runs a Windows version with a build number lower than the thresholds listed AND has Windows Push Notifications enabled or in use.

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 10.0.17763.8880 / 10.0.19044.7417 / 10.0.19045.7417 or later
Fixed in 10.0.17763.888010.0.19044.741710.0.19045.7417
Interim mitigation

Apply the applicable Windows security update once released by Microsoft to address the race condition in Push Notifications. Since this is a local privilege escalation, ensure attackers already on the system have limited initial access through proper least-privilege configurations.

Recommended fix High confidence

Windows 10 1809: 10.0.17763.8880 | Windows 10 21h2: 10.0.19044.7417 | Windows 10 22h2: 10.0.19045.7417 | Windows 11 23h2: 10.0.22631.7219 | Windows 11 24h2: 10.0.26100.8655 | Windows 11 25h2: 10.0.26200.8655 | Windows 11 26h1: 10.0.28000.2269 | Windows Server 2019: 10.0.17763.8880

  1. Open Settings > Update & Security > Windows Update
  2. Click 'Check for updates' to download and install the latest security updates
  3. Restart the system after updates are installed
  4. Verify the installation by running 'winver' to confirm your build number meets or exceeds the minimum fixed version for your Windows edition
Caveat Standard Windows security update with no expected breaking changes; as a local privilege escalation fix, apply promptly

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
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

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-2026-42978 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