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Windows 10Operating system · Microsoft

CVE-2016-3342

HIGH · 7.8 CVSS v3.0 Published 2016-11-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
81/100
Remediation priority · High
No privileges

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
The Common Log File System (CLFS) driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, and 1607, and Windows Server 2016 allows local users to gain privileges via a crafted application, aka "Windows Common Log File System Driver Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-0026, CVE-2016-3332, CVE-2016-3333, CVE-2016-3334, CVE-2016-3335, CVE-2016-3338, CVE-2016-3340, CVE-2016-3343, and CVE-2016-7184.

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 · high confidence

A local privilege escalation vulnerability in the Windows Common Log File System (CLFS) driver allows a low-privileged user to elevate to higher system privileges by running a specially crafted application. The vulnerability exists in the kernel-mode CLFS.sys driver which fails to properly validate certain user-mode requests.

MitigationApply Microsoft security update MS16-111 or later, which patches the CLFS driver vulnerability. Deploy through standard Windows Update or enterprise patch management systems.

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 10Operating system
Affected:all versions= 1511= 1607
Windows 7Operating system
Affected:all versions
Windows 8.1Operating system
Affected:all versions
Windows Rt 8.1Operating system
Affected:all versions
Windows Server 2008Operating system
Affected:all versions= r2
Windows Server 2012Operating system
Affected:all versions= r2
Windows Server 2016Operating system
Affected:all versions
Windows VistaOperating system
Affected:all versions

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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 version is affected
    Run 'winver' or 'systeminfo' or check the registry key HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion. Identify the Windows version and build number.
    Affected if The system runs Windows 10 (any version, including 1511 and 1607), Windows 7, Windows 8.1, Windows RT 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, or Windows Vista.
  2. Locate CLFS.sys driver file
    Navigate to C:\Windows\System32\drivers\CLFS.sys and view the file properties, or run 'driverquery /v | findstr CLFS' to list the driver details.
    Affected if The CLFS.sys driver file exists on the system (required for this vulnerability).
  3. Check CLFS.sys driver version
    Right-click CLFS.sys in File Explorer, go to Properties > Details, and note the File Version. Alternatively, run 'wmic path win32_PnPSignedDriver where "DeviceName='Common Log File System'" get DriverVersion' or use a tool like sigcheck.exe.
    Affected if The driver version is older than the version shipped with MS16-111 patch. Compare your version against the patched CLFS.sys version for your Windows build.
  4. Verify MS16-111 patch installation
    Run 'wmic qfe list' or check 'Control Panel > Programs and Features > View installed updates' to list installed hotfixes. Search for KB3186972 (the update for this CVE).
    Affected if The security update KB3186972 (MS16-111) is NOT installed on the system.

The system is affected if it runs any of the listed Windows versions AND lacks the MS16-111 (KB3186972) patch, which can be verified by checking for the missing update or an unpatched CLFS.sys driver version.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft security update MS16-111 or later, which patches the CLFS driver vulnerability. Deploy through standard Windows Update or enterprise patch management systems.

Fix this in Windows 10 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2016-3342 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