SYSTEM privilege escalation via readable registry hives
Published Jul 22, 2021 · Updated Aug 10, 2026
Privilege escalation in Microsoft Windows 10 Version 1809 through 21H1 allows local users to execute code with SYSTEM privileges. Overly permissive inherited ACLs grant BUILTIN\Users read and execute access to the SAM, SYSTEM, and SECURITY registry hives in %windir%\system32\config, including copies captured by Volume Shadow Copy Service. Exploitation requires existing local code execution and an accessible shadow copy, after which extracted credential material enables full SYSTEM control.
Summary
What happened
Privilege escalation in Microsoft Windows 10 Version 1809 through 21H1 allows local users to execute code with SYSTEM privileges. Overly permissive inherited ACLs grant BUILTIN\Users read and execute access to the SAM, SYSTEM, and SECURITY registry hives in %windir%\system32\config, including copies captured by Volume Shadow Copy Service. Exploitation requires existing local code execution and an accessible shadow copy, after which extracted credential material enables full SYSTEM control.
The record
- CVE
- CVE-2021-36934
- Published
- Jul 22, 2021
- Updated
- Aug 10, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 21H1
- Classifications
- CWE-1220, T1068, T1003.002
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 22, 2021CVE publishedPublication date reported by the CVE source.
- Aug 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.0 <10.0.19043.1165
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- HiveNightmarefunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Microsoft Windows SAM Local Privilege Escalation Vulnerabilityknown exploited catalog
Technologies
Your stack
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Your stack
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