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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 13 Jun 2022. Known ransomware use
Windows 10 1709Operating system · Microsoft

CVE-2020-0638

HIGH · 7.8 CVSS v3.1 Published 2020-01-14
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
96/100
Remediation priority · Urgent
In the wild Ransomware Zero-click Patch available

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
An elevation of privilege vulnerability exists in the way the Update Notification Manager handles files.To exploit this vulnerability, an attacker would first have to gain execution on the victim system, aka 'Update Notification Manager Elevation of Privilege Vulnerability'.

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

This is an elevation of privilege vulnerability in Windows Update Notification Manager that stems from improper file handling. An attacker must first achieve code execution on the target system before leveraging this flaw to escalate privileges to higher integrity levels. The vulnerability allows a locally authenticated attacker to gain elevated system privileges.

MitigationApply the Microsoft security updates for CVE-2020-0638, which is addressed in the relevant Windows security bulletins. Ensure patch management processes include coverage for Windows Update components.

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 1709Operating system
Affected:all versions
Windows 10 1803Operating system
Affected:all versions
Windows 10 1809Operating system
Affected:all versions
Windows 10 1903Operating system
Affected:all versions
Windows 10 1909Operating system
Affected:all versions
Windows Server 1803Operating system
Affected:all versions
Windows Server 1903Operating system
Affected:all versions
Windows Server 1909Operating 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
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 Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the installed Windows version and build
    Affected if The version is Windows 10 1709, 1803, 1809, 1903, 1909, or Windows Server 1803, 1903, 1909 (any build)
  2. Verify Update Notification Manager component presence
    Check for the presence of 'wuaueng.dll' in the system (located in C:\Windows\System32) - this is the Windows Update Notification Manager engine DLL
    Affected if The filewuaueng.dll exists on the system (required for the vulnerability to apply)
  3. Confirm security update KB4541335 installation
    Run 'wmic qfe list' or check Windows Update history for the presence of KB4541335
    Affected if KB4541335 is NOT installed - the system lacks the security patch for this CVE

You are affected if you run any version of Windows 10 1709, 1803, 1809, 1903, 1909, or Windows Server 1803, 1903, 1909 AND the Update Notification Manager component is present AND security update KB4541335 has not 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
Patch available Apply the vendor patch
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Apply the Microsoft security updates for CVE-2020-0638, which is addressed in the relevant Windows security bulletins. Ensure patch management processes include coverage for Windows Update components.

Recommended fix Moderate confidence

Upgrade to a currently supported Windows 10 version (20H2 or later) or Windows Server 2019/2022 for long-term security support

  1. Apply the March 2020 Windows Security Update that addresses CVE-2020-0638
  2. For Windows 10 1909: Install KB4551762 (March 2020 Security Update)
  3. For Windows 10 1903: Install KB4551762 (March 2020 Security Update)
  4. For Windows 10 1809: Install KB4549949 (March 2020 Security Update)
  5. For Windows 10 1803: Install KB4550960 (March 2020 Security Update)
  6. For Windows 10 1709: Install KB4550905 (March 2020 Security Update)
  7. For Windows Server 1909: Install KB4551762 (March 2020 Security Update)
  8. For Windows Server 1903: Install KB4551762 (March 2020 Security Update)
Caveat Windows 10 versions 1709, 1803, and 1809 have reached end of support; continuing to use them poses security risks

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

Fix this in Windows 10 1709 Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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-2020-0638 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