High 7.8Known exploited (CISA KEV)Published Jul 22, 2021

CVE-2021-36934Windows Elevation of Privilege Vulnerability

Updated under an hour ago (Oct 27, 2026, 11:50 AM ET)

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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Every CVE for Microsoft Windows 10 Version 1809

Exploited in the last 30 days

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

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

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934	vendor-advisory, patch
http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html	third-party-advisory, vdb-entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934	patch, vendor-advisory
https://www.kb.cert.org/vuls/id/506989	third-party-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934	us-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.