dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-34330

HIGH · 7.8 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 →
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 Win32K - GRFX 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 Win32K GRFX (graphics subsystem) where concurrent execution with improper synchronization on shared resources allows a locally authorized attacker to elevate privileges to higher integrity levels.

MitigationApply the Microsoft security update for CVE-2026-34330 when released. Until then, limit local administrative access and monitor for suspicious process activity targeting the Win32K subsystem.

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 1607Operating system
Affected:< 10.0.14393.9140
Windows 10 1809Operating system
Affected:< 10.0.17763.8755
Windows 10 21h2Operating system
Affected:< 10.0.19044.7291
Windows 10 22h2Operating system
Affected:< 10.0.19045.7291
Windows 11 23h2Operating system
Affected:< 10.0.22631.7079
Windows 11 24h2Operating system
Affected:< 10.0.26100.8390
Windows 11 25h2Operating system
Affected:< 10.0.26200.8390
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113

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. Identify Windows version and build number
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to retrieve the exact Windows version and build number
    Affected if The installed build number falls below the fixed version for that Windows release (e.g., below 10.0.14393.9140 for Windows 10 1607, below 10.0.17763.8755 for Windows 10 1809, etc.)
  2. Confirm Win32K subsystem is present
    The Win32K graphics subsystem (win32k.sys) is a kernel component present by default on all Windows installations; verify existence via 'sc query win32k' or check that the driver loads at runtime
    Affected if Win32K subsystem is present (which is the default state for all affected Windows versions)
  3. Check current patch status
    Run 'wmic qfe list' or 'Get-HotFix' in PowerShell to enumerate installed security updates; look for the specific KB or patch addressing CVE-2026-34330
    Affected if The security update for CVE-2026-34330 is NOT installed and the Windows version/build matches an affected version range

The system is affected if it runs any of the affected Windows 10 or 11 versions AND the build number is below the fixed threshold AND the CVE-2026-34330 security update is not installed.

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 / 10.0.19044.7291 or later
Fixed in 10.0.14393.914010.0.17763.875510.0.19044.7291
Interim mitigation

Apply the Microsoft security update for CVE-2026-34330 when released. Until then, limit local administrative access and monitor for suspicious process activity targeting the Win32K subsystem.

Recommended fix High confidence

Install the latest Windows Security Update from Windows Update that includes the fix for this vulnerability (CVE-2026-34330)

  1. Open Windows Settings on the affected system
  2. Navigate to Update & Security > Windows Update
  3. Click 'Check for updates' to download and install all available updates
  4. After updates are installed, restart the system to apply changes
  5. Verify the installed Windows version matches or exceeds the fixed release: Windows 10 1607: 10.0.14393.9140 | Windows 10 1809: 10.0.17763.8755 | Windows 10 21h2: 10.0.19044.7291 | Windows 10 22h2: 10.0.19045.7291 | Windows 11 23h2: 10.0.22631.7079 | Windows 11 24h2: 10.0.26100.8390 | Windows 11 25h2: 10.0.26200.8390 | Windows 11 26h1: 10.0.28000.2113
Caveat Standard Windows update - may require restart and could include other cumulative updates

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.

Scan for this in your stack

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dbcve dependency scanner

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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-2026-34330 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