dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-25166

HIGH · 7.8 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 10.0.14393.8957 / 10.0.17763.8511 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
Deserialization of untrusted data in Windows System Image Manager allows an authorized attacker to execute code 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

Windows System Image Manager contains a deserialization vulnerability where it processes untrusted data without proper validation. An authorized attacker with local system access could exploit this to execute arbitrary code by manipulating the deserialized objects.

MitigationApply Microsoft security updates for Windows System Image Manager when available. Until then, restrict access to trusted personnel only and monitor for suspicious WSIM usage.

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:< 10.0.14393.8957
Windows 10 1809Operating system
Affected:< 10.0.17763.8511
Windows 10 21h2Operating system
Affected:< 10.0.19044.7058
Windows 10 22h2Operating system
Affected:< 10.0.19045.7058
Windows 11 23h2Operating system
Affected:< 10.0.22631.6783
Windows 11 24h2Operating system
Affected:< 10.0.26100.7979
Windows 11 25h2Operating system
Affected:< 10.0.26200.7979
Windows 11 26h1Operating system
Affected:< 10.0.28000.1719

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. Confirm Windows System Image Manager is installed
    Check for the presence of simmgr.dll in the System32 folder (typically C:\Windows\System32\simmgr.dll) or verify WSIM is available via Windows Features or the Windows ADK installation.
    Affected if WSIM is present on the system, making it a potential target for exploitation.
  2. Determine the installed Windows build version
    Open Command Prompt or PowerShell and run 'winver' or 'systeminfo | findstr /C:"Build"' to retrieve the Windows build number.
    Affected if The build number falls within any of these affected ranges: Windows 10 1607 builds before 14393.8957, Windows 10 1809 builds before 17763.8511, Windows 10 21h2 builds before 19044.7058, Windows 10 22h2 builds before 19045.7058, Windows 11 23h2 builds before 22631.6783, Windows 11 24h2 builds before
  3. Identify if the vulnerability is still unpatched
    Check Windows Update history or the Microsoft Security Response Center advisories for any installed security updates addressing CVE-2026-25166 for Windows System Image Manager.
    Affected if No corresponding security update for this CVE has been installed, leaving the deserialization vulnerability unmitigated.

A user is affected if Windows System Image Manager is installed, the Windows build version is lower than the upper bounds listed in the affected version ranges, and no vendor security patch for this CVE has been applied.

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 10.0.14393.8957 / 10.0.17763.8511 / 10.0.19044.7058 or later
Fixed in 10.0.14393.895710.0.17763.851110.0.19044.7058
Interim mitigation

Apply Microsoft security updates for Windows System Image Manager when available. Until then, restrict access to trusted personnel only and monitor for suspicious WSIM usage.

Recommended fix High confidence

Upgrade to Windows 10 build 10.0.14393.8957 or later (1607), 10.0.17763.8511 or later (1809), 10.0.19044.7058 or later (21h2), 10.0.19045.7058 or later (22h2); or Windows 11 build 10.0.22631.6783 or later (23h2), 10.0.26100.7979 or later (24h2), 10.0.26200.7979 or later (25h2), 10.0.28000.1719 or la

  1. Open Windows Settings and navigate to Update & Security > Windows Update
  2. Check for updates and install all available security updates
  3. If using enterprise deployment tools (WSUS, SCCM, Intune), ensure the following build versions are approved and deployed: Windows 10 1607 build 10.0.14393.8957, Windows 10 1809 build 10.0.17763.8511, Windows 10 21h2 build 10.0.19044.7058, Windows 10 22h2 build 10.0.19045.7058, Windows 11 23h2 build 10.0.22631.6783, Windows 11 24h2 build 10.0.26100.7979, Windows 11 25h2 build 10.0.26200.7979, Windo
  4. Restart the system after updates are installed
  5. Verify the installed build version matches or exceeds the fixed versions by running 'winver' or 'systeminfo' from command prompt
Caveat Standard Windows update with no expected breaking changes; apply after normal testing procedures

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2026-25166 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