CVE-2021-36934
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 · uneditedAn elevation of privilege vulnerability exists because of overly permissive Access Control Lists (ACLs) on multiple system files, including the Security Accounts Manager (SAM) database. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. An attacker must have the ability to execute code on a victim system to exploit this vulnerability. After installing this security update, you must manually delete all shadow copies of system files, including the SAM database, to fully mitigate this vulnerabilty. Simply installing this security update will not fully mitigate this vulnerability. See KB5005357- Delete Volume Shadow Copies.
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 confidenceWindows SAM database and related system files have overly permissive ACLs allowing low-privileged users to read sensitive data including password hashes. An attacker with code execution can leverage this to escalate to SYSTEM privileges by exploiting the weak ACLs on the Security Accounts Manager database and other protected system files.
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< 10.0.19043.1165CVSS 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 build versionRun 'winver' or 'systeminfo | findstr /C:"Build"' to obtain the OS build numberAffected if Build number is below 17763.2114 (1809), 18363.1734 (1909), 19041.1165 (2004), 19042.1165 (20h2), or 19043.1165 (21h1)
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Inspect SAM file ACLsRun 'icacls %SystemRoot%\System32\config\SAM' to view access control listsAffected if Users group orAuthenticated Users have Read access (output shows 'Users:(I)(R)' or similar read permissions to the SAM file)
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Check for vulnerable system filesRun 'dir /a %SystemRoot%\System32\config\SAM' to confirm the SAM file exists and is accessibleAffected if SAM file is present and readable by standard user accounts
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Detect Volume Shadow CopiesRun 'vssadmin list shadows' or 'Get-WmiObject Win32_ShadowCopy' to list existing shadow copiesAffected if Any volume shadow copies exist on the system drive, which could contain the vulnerable SAM database
User is affected if running a Windows 10 version within the specified build ranges AND the SAM file is readable by standard users AND volume shadow copies exist that could expose the original vulnerable SAM data.
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
Install the Microsoft security update AND manually delete all volume shadow copies using vssadmin or equivalent tools per KB5005357; simply patching does NOT fully remediate this vulnerability.
Windows 10 1809 (10.0.17763.2114+), Windows 10 1909 (10.0.18363.1734+), Windows 10 2004 (10.0.19041.1165+), Windows 10 20h2 (10.0.19042.1165+), Windows 10 21h1 (10.0.19043.1165+)
- Install the applicable security update for your Windows 10 version (KB5005393 or later monthly rollup)
- After installing the security update, delete all shadow copies to remove copies of the SAM database: Open Command Prompt as Administrator and run 'vssadmin delete shadows /all /quiet'
- Alternatively, use the steps in Microsoft KB5005357 to delete volume shadow copies
- Verify the shadow copies have been deleted using 'vssadmin list shadows'
- Ensure the system files have corrected ACLs by reviewing permissions on %systemroot%\system32\config\SAM
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-36934 — 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-2021-36934 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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- Version or environment caveats, and links to real fixes
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