CVE-2021-36934
An elevation of privilege vulnerability exists because of overly permissive Access Control Lists (ACLs) on multiple system files, including the…
Browse: All 2021 CVEs · All vendors
- CVSS score
- 7.8 High
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- CISA KEV
- Yes — actively exploited (added 2022-02-10, remediation due 2022-02-24)
- Weakness (CWE)
- NVD-CWE-Other
- Published
- 2021-07-22
- Last modified
- 2026-08-10
- NVD status
- Analyzed
Description
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.
Affected products
- microsoft windows 10 1809
- microsoft windows 10 1909
- microsoft windows 10 2004
- microsoft windows 10 20h2
- microsoft windows 10 21h1
Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.
Required action (CISA)
Apply updates per vendor instructions. Federal remediation deadline: 2022-02-24.
How to prioritize this
This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score. For the actively exploited vulnerabilities that matter this week, read The Exploit HQ daily security brief.
References
- https://msrc.microsoft.com/update-guide/vulnerability/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
FAQ
Is CVE-2021-36934 actively exploited?
Yes. CISA added CVE-2021-36934 to its Known Exploited Vulnerabilities (KEV) catalog on 2022-02-10, with a federal remediation deadline of 2022-02-24. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.
What is the CVSS score of CVE-2021-36934?
CVE-2021-36934 has a CVSS base score of 7.8 (High). Its vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Related vulnerabilities
- CVE-2026-96951 — Microsoft Windows
- CVE-2026-81963 — Microsoft Windows
- CVE-2026-85880 — Microsoft Windows
- CVE-2008-4250 — Microsoft Windows
- CVE-2026-32202 — Microsoft Windows
- CVE-2025-60710 — Microsoft Windows
Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.
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