CVE-2021-36948
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 · uneditedWindows Update Medic Service 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 confidenceWindows Update Medic Service contains an elevation of privilege vulnerability that allows a low-privileged attacker to gain higher-level system privileges. The Windows Update Medic Service is designed to repair Windows Update components, and the vulnerability stems from improper privilege handling within this service.
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< 10.0.17763.2114< 10.0.18363.1734< 10.0.19041.1165< 10.0.19042.1165< 10.0.19043.1165< 10.0.19041.1165< 10.0.17763.2114< 10.0.19042.1165CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check Windows version and build numberRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the Windows build numberAffected if The build number is lower than the thresholds in the affected versions list (e.g., below 17763.2114 for Windows 10 1809/Server 2019, below 18363.1734 for Windows 10 1909, below 19041.1165 for Windows 10 2004/Server 2004, below 19042.1165 for Windows 10 20h2/Server 20h2, below 19043.1165 for Windows
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Verify WaaSMedicSvc service existsRun 'sc query WaaSMedicSvc' in Command Prompt or 'Get-Service -Name WaaSMedicSvc' in PowerShellAffected if The service is found on the system (the vulnerability applies to systems where this service exists)
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Check WaaSMedicSvc service statusRun 'sc queryex WaaSMedicSvc' or check the service status in Services.mscAffected if The service is in a running state (the vulnerability requires the service to be running for local privilege escalation)
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Confirm the installed security updateRun 'powershell -Command "Get-HotFix | Where-Object {$_.Description -like '*Security Update*' -and $_.HotFixID -like '*KB5005678*' -or $_.HotFixID -like '*KB5005690*'}"' or check Windows Update history for August 2021 security updatesAffected if The specific KB5005678 or KB5005690 (or later security updates containing the fix) are NOT installed
A system is affected if it runs a vulnerable Windows 10/Server version with a build number below the thresholds AND has the WaaSMedicSvc service running AND lacks the August 2021 security updates for this CVE.
Generated from the published advisory. Verify against your own configuration.
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 · scoped10.0.17763.211410.0.18363.173410.0.19041.1165
Apply the relevant Microsoft security update for CVE-2021-36948 via Windows Update or manual patch deployment to remediate the privilege escalation vulnerability.
Upgrade to Windows 10 1809 build 10.0.17763.2114 or later; Windows 10 1909 build 10.0.18363.1734 or later; Windows 10 2004/Server 2004 build 10.0.19041.1165 or later; Windows 10 20h2/Server 20h2 build 10.0.19042.1165 or later; Windows 10 21h1 build 10.0.19043.1165 or later; Windows Server 2019 build
- Identify the current Windows version by running 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'
- Determine which Windows 10 or Windows Server version is running from the version list
- Apply the appropriate Windows security update that includes the fix for CVE-2021-36948, or upgrade to a supported version with a build number at or above the fixed version
- Restart the system as required by the update
- Verify the installed build number matches or exceeds: Windows 10 1809: 10.0.17763.2114, Windows 10 1909: 10.0.18363.1734, Windows 10 2004/Server 2004: 10.0.19041.1165, Windows 10 20h2/Server 20h2: 10.0.19042.1165, Windows 10 21h1: 10.0.19043.1165, Windows Server 2019: 10.0.17763.2114
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-36948 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-36948 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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