CVE-2021-36934Windows Elevation of Privilege Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft Windows 10 Version 1809 and 4 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Feb 10, 2022; federal agencies had to remediate by Feb 24, 2022. Treat that date as your deadline.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:T/RC:C
- Weakness (CWE)
- Not given
- Known exploited
- Added to CISA KEV Feb 10, 2022; federal remediation due Feb 24, 2022Apply updates per vendor instructions.
- EPSS (exploitation in the next 30 days)
- 67.25% (percentile 99)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Aug 10, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Windows 10 Version 1809 microsoft:windows_10_1809 | from 10.0.17763.0 before 10.0.17763.2114 | CNA record |
Microsoft Windows 10 Version 1909 microsoft:windows_10_1909 | from 10.0.0 before 10.0.18363.1734 | CNA record |
Microsoft Windows 10 Version 2004 microsoft:windows_10_2004 | from 10.0.0 before 10.0.19041.1165 | CNA record |
Microsoft Windows 10 Version 20H2 microsoft:windows_10_20h2 | from 10.0.0 before 10.0.19042.1165 | CNA record |
Microsoft Windows 10 Version 21H1 microsoft:windows_10_21h1 | from 10.0.0 before 10.0.19043.1165 | CNA record |
microsoft windows_10_1809 microsoft:windows_10_1809 | before 10.0.17763.2114 | NVD |
microsoft windows_10_1909 microsoft:windows_10_1909 | before 10.0.18363.1734 | NVD |
microsoft windows_10_2004 microsoft:windows_10_2004 | before 10.0.19041.1165 | NVD |
microsoft windows_10_20h2 microsoft:windows_10_20h2 | before 10.0.19042.1165 | NVD |
microsoft windows_10_21h1 microsoft:windows_10_21h1 | before 10.0.19043.1165 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934vendor-advisory, patch
- http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.htmlthird-party-advisory, vdb-entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934patch, vendor-advisory
- https://www.kb.cert.org/vuls/id/506989third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.