CVE-2021-36934: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-04-03T20:19:26.606Z. This file is automatically regenerated every 30 minutes by the CVE AI enrichment job using web sources (NVD, MITRE, CISA KEV, GitHub).

Executive Technical Summary

An 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 .

• Context preserved from previous revision: An 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 . Notes: 渗透测试有关的POC、EXP、脚本、提权、小工具等---About penetration-testing python-script poc getshell csrf xss cms php-getshell domainmod-xss csrf-webshell cobub-razor cve rce sql sql-poc poc-exp bypass oa-getshell cve-cms

Technical Details

• CVE: CVE-2021-36934
• KEV date added: 2022-02-10
• KEV due date: 2022-02-24
• NVD published: 2021-07-22
• NVD modified: 2026-02-25
• MITRE modified: 2025-10-21
• CVSS base score: 7.8
• CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• CVSS exploitability score: 1.8
• CVSS impact score: 5.9
• Attack vector: Local
• Attack complexity: Low
• Privileges required: Low
• User interaction: None
• Scope: Unchanged
• Confidentiality impact: High
• Integrity impact: High
• Availability impact: High

Versions and Products Impacted

• microsoft / windows 10 1809 (versions: < 10.0.17763.2114)
• microsoft / windows 10 1909 (versions: < 10.0.18363.1734)
• microsoft / windows 10 2004 (versions: < 10.0.19041.1165)
• microsoft / windows 10 20h2 (versions: < 10.0.19042.1165)
• microsoft / windows 10 21h1 (versions: < 10.0.19043.1165)
• Microsoft / Windows 10 Version 1809 (versions: 10.0.0)
• Microsoft / Windows 10 Version 1909 (versions: 10.0.0)
• Microsoft / Windows 10 Version 21H1 (versions: 10.0.0)
• Microsoft / Windows 10 Version 2004 (versions: 10.0.0)
• Microsoft / Windows 10 Version 20H2 (versions: 10.0.0)

Weakness Classification

• NVD-CWE-Other
• CWE-noinfo Not enough information

Repositories for Lab Validation (Public Examples)

• Mr-xn/Penetration_Testing_POC | stars: 7295 | updated: 2026-04-03 | https://github.com/Mr-xn/Penetration_Testing_POC
  Notes: 渗透测试有关的POC、EXP、脚本、提权、小工具等---About penetration-testing python-script poc getshell csrf xss cms php-getshell domainmod-xss csrf-webshell cobub-razor cve rce sql sql-poc poc-exp bypass oa-getshell cve-cms
• Ostorlab/KEV | stars: 608 | updated: 2026-03-23 | https://github.com/Ostorlab/KEV
  Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

People and Organizations Mentioned

• microsoft
• Windows
• Mr-xn
• Ostorlab

Practical Defensive Validation (Authorized Only)

1. Use only isolated environments and systems you own or are explicitly authorized to test.
2. Snapshot infrastructure before validation and preserve baseline logs (EDR, SIEM, OS, app).
3. Create low-privilege users on microsoft / windows 10 1809 (versions: < 10.0.17763.2114) and validate that patching blocks unauthorized admin-level actions.
4. Compare token/privilege transitions in Windows Event Logs before and after remediation.
5. Tune detections for unusual group membership changes and SYSTEM-level process launches from user sessions.

References

• NVD record: https://nvd.nist.gov/vuln/detail/CVE-2021-36934
• MITRE CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36934
• CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• CISA KEV JSON feed: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
• KEV notes: https://nvd.nist.gov/vuln/detail/CVE-2021-36934
• http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934
• https://www.kb.cert.org/vuls/id/506989
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934
• Repository example: https://github.com/Mr-xn/Penetration_Testing_POC
• Repository example: https://github.com/Ostorlab/KEV

This content is for defensive security training and authorized validation only.