Which products and versions are affected by CVE-2021-36934?

Affected: Windows 10 1809 (Microsoft) versions 10.0.17763.2114, 10.0.18363.1734, 10.0.19041.1165; Windows 10 1909 (Microsoft) versions 10.0.18363.1734; Windows 10 2004 (Microsoft), among others. The full list is in the CVE brief.

Is CVE-2021-36934 being exploited in the wild?

It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 9, 2022.

Is CVE-2021-36934 in the CISA KEV catalog?

Yes. It was added on Feb 10, 2022 with a federal remediation due date of Feb 24, 2022.

Is there a public exploit for CVE-2021-36934?

Public exploit code is available.

Is there a fix for CVE-2021-36934?

Fixed versions are available, including Windows 10 1809 10.0.17763.2114, Windows 10 1809 10.0.18363.1734, Windows 10 1809 10.0.19041.1165.

How urgently should CVE-2021-36934 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2021-36934

HighExploitedPublic exploit

HiveNightmare — Windows SAM registry hive disclosure

Published Jul 22, 2021 · Updated Aug 10, 2026 · Also known as Hive Nightmare, HiveNightmare, Serious SAM, SeriousSAM

Key Facts

Patch immediately

CVE-2021-36934 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1809 (Microsoft), Windows 10 1909 (Microsoft), Windows 10 2004 (Microsoft) and 2 more products.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 9, 2022. Public exploit code is available.
EPSS estimates a 67% probability of exploitation in the next 30 days.
Fixed versions are available, including Windows 10 1809 10.0.17763.2114, Windows 10 1809 10.0.18363.1734, Windows 10 1809 10.0.19041.1165.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

7.8

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

67%

Higher than 99.2% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2021-36934 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

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.

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CISA KEV	Feb 10, 2022	Feb 24, 2022	Not reported
Industry KEV feed	Feb 9, 2022	Feb 24, 2022	Not reported
CIRCL KEV	Feb 10, 2022	Feb 24, 2022	Not reported
ENISA EUVD	Feb 10, 2022	n/a	Not reported

Required action: Apply updates per vendor instructions.

Affected Products

17 affected entries in total

Product	Affected versions	Fixed in
Windows 10 1809Microsoft	10.0.17763.2114, 10.0.18363.1734, 10.0.19041.1165	10.0.17763.2114
Windows 10 1909Microsoft	10.0.18363.1734	10.0.18363.1734
Windows 10 2004Microsoft	See advisory	10.0.19041.1165
windows 10 20H2Microsoft	10.0.19042.1165	10.0.19042.1165
windows 10 21H1Microsoft	10.0.19043.1165	10.0.19043.1165

Patched Releases

Windows 10 1809

10.0.17763.2114, 10.0.18363.1734, 10.0.19041.1165

Windows 10 1909

10.0.18363.1734

Windows 10 2004

10.0.19041.1165

windows 10 20H2

10.0.19042.1165

windows 10 21H1

10.0.19043.1165

Timeline

Publicly disclosed
Jul 22, 2021
Added to Industry KEV feed
Feb 9, 2022
Added to CISA KEV
Feb 10, 2022
Added to CIRCL KEV
Feb 10, 2022
Added to ENISA EUVD
Feb 10, 2022
Last updated
Aug 10, 2026

References

6 more references in the full CVE brief

FAQ

Common Questions.

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.
Affected: Windows 10 1809 (Microsoft) versions 10.0.17763.2114, 10.0.18363.1734, 10.0.19041.1165; Windows 10 1909 (Microsoft) versions 10.0.18363.1734; Windows 10 2004 (Microsoft), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 9, 2022.
Yes. It was added on Feb 10, 2022 with a federal remediation due date of Feb 24, 2022.
Public exploit code is available.
Fixed versions are available, including Windows 10 1809 10.0.17763.2114, Windows 10 1809 10.0.18363.1734, Windows 10 1809 10.0.19041.1165.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2021-36934 Running On Your Attack Surface?

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