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Windows 11 24h2Operating system · Microsoft

CVE-2026-42896

HIGH · 7.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 10.0.26100.8457 / 10.0.26100.32860 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
Integer overflow or wraparound in Windows DWM Core Library 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

Integer overflow or wraparound vulnerability in Windows DWM Core Library (Desktop Window Manager) that can be exploited locally to elevate privileges. The vulnerability allows an authenticated attacker to potentially execute arbitrary code with elevated system privileges by exploiting the arithmetic error in the DWM process.

MitigationApply Microsoft security updates for Windows when available. Until patch release, restrict local system access to trusted administrators only and monitor for suspicious processes interacting with DWM core libraries.

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 11 24h2Operating system
Affected:< 10.0.26100.8457
Windows 11 25h2Operating system
Affected:< 10.0.26200.8457
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113
Windows Server 2025Operating system
Affected:< 10.0.26100.32860

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 installed Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to display the Windows version and build number
    Affected if The version is Windows 11 24h2 with build < 10.0.26100.8457, Windows 11 25h2 with build < 10.0.26200.8457, Windows 11 26h1 with build < 10.0.28000.2113, or Windows Server 2025 with build < 10.0.26100.32860
  2. Confirm DWM process is running
    Open Task Manager, go to the Processes tab, and look for 'Desktop Window Manager' (dwm.exe) under System Processes, or run 'tasklist /FI "IMAGENAME eq dwm.exe"' in command prompt
    Affected if DWM is running (this is the process containing the vulnerable code)
  3. Verify local authenticated user context
    Run 'whoami' in command prompt to identify the current user account
    Affected if The current user is a local authenticated user (the vulnerability requires an authenticated attacker with local system access)

Your environment is affected if you are running any of the listed Windows versions with a build number lower than the specified threshold AND DWM is active on the system.

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 10.0.26100.8457 / 10.0.26100.32860 / 10.0.26200.8457 or later
Fixed in 10.0.26100.845710.0.26100.3286010.0.26200.8457
Interim mitigation

Apply Microsoft security updates for Windows when available. Until patch release, restrict local system access to trusted administrators only and monitor for suspicious processes interacting with DWM core libraries.

Recommended fix High confidence

Windows 11 24h2: build 10.0.26100.8457 or later | Windows 11 25h2: build 10.0.26200.8457 or later | Windows 11 26h1: build 10.0.28000.2113 or later | Windows Server 2025: build 10.0.26100.32860 or later

  1. Open Windows Settings on the affected Windows 11 or Windows Server 2025 machine
  2. Navigate to Windows Update (Settings > Windows Update)
  3. Click 'Check for updates' to download and install the latest security updates
  4. Verify the installed build version matches or exceeds the fixed version: Windows 11 24h2 should be >= 10.0.26100.8457, Windows 11 25h2 should be >= 10.0.26200.8457, Windows 11 26h1 should be >= 10.0.28000.2113, Windows Server 2025 should be >= 10.0.26100.32860
  5. Restart the system if prompted to complete the installation
Caveat Standard Windows update risks apply - ensure backups and test in staging environment before broad deployment

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

Fix this in Windows 11 24h2 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-42896 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