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Windows 11 24h2Operating system · Microsoft

CVE-2026-48566

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 10.0.26100.8390 / 10.0.26100.32772 or later.
See remediation →
57/100
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
Out-of-bounds read 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

An out-of-bounds read vulnerability exists in the Windows DWM Core Library (Desktop Window Manager). The vulnerability allows a local, authorized attacker to read memory beyond allocated buffer boundaries, potentially exposing sensitive information from the system's memory space.

MitigationApply the relevant Microsoft security update for the Windows DWM Core Library through Windows Update or your organization's patch management process. Verify the update is successfully installed and test that DWM functionality remains operational.

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:< 10.0.26100.8390
Windows 11 25h2Operating system
Affected:< 10.0.26200.8390
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113
Windows Server 2025Operating system
Affected:< 10.0.26100.32772

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
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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
    Run 'winver' or 'systeminfo | findstr /C:"Build Number"' to obtain the full OS build version
    Affected if The build number falls below 10.0.26100.8390 for 24h2, 10.0.26200.8390 for 25h2, 10.0.28000.2113 for 26h1, or 10.0.26100.32772 for Server 2025
  2. Verify dwmcore.dll version
    Open File Explorer, navigate to C:\Windows\System32\dwmcore.dll, right-click and select Properties, then view the Details tab for the File version
    Affected if The dwmcore.dll file version is lower than the corresponding fix version for your Windows build (24h2/25h2/26h1/Server 2025)
  3. Confirm DWM service is running
    Open Task Manager, go to the Services tab, locate 'Desktop Window Manager' (dwm.exe) and verify its status, or run 'Get-Service Dwm*' in PowerShell
    Affected if The Desktop Window Manager service is running (vulnerability is only exploitable when DWM is active)
  4. Confirm local access to the system
    Verify you have an active user session on the system or can establish one (the vulnerability requires a locally authenticated attacker)
    Affected if A user with local authentication rights can log into the system, which is the typical condition for workstations and servers with interactive logon

You are affected if your Windows build is one of the listed versions AND its number is below the specified threshold AND the DWM service is running on your 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 10.0.26100.8390 / 10.0.26100.32772 / 10.0.26200.8390 or later
Fixed in 10.0.26100.839010.0.26100.3277210.0.26200.8390
Interim mitigation

Apply the relevant Microsoft security update for the Windows DWM Core Library through Windows Update or your organization's patch management process. Verify the update is successfully installed and test that DWM functionality remains operational.

Recommended fix High confidence

Windows 11 24h2 build 10.0.26100.8390 | Windows 11 25h2 build 10.0.26200.8390 | Windows 11 26h1 build 10.0.28000.2113 | Windows Server 2025 build 10.0.26100.32772

  1. Open Settings > Windows Update and check for available updates
  2. Install all pending security updates from Microsoft
  3. Restart the system if prompted to complete the update installation
  4. Verify the installed Windows version meets or exceeds the fixed build number for your product: Windows 11 24h2 should be 10.0.26100.8390 or later, Windows 11 25h2 should be 10.0.26200.8390 or later, Windows 11 26h1 should be 10.0.28000.2113 or later, Windows Server 2025 should be 10.0.26100.32772 or later

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

Fix this in Windows 11 24h2 Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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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-2026-48566 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