CVE-2021-36934

7.8 HIGH CISA KEV - Actively Exploited
Published: July 22, 2021 Modified: October 30, 2025

Description

<p>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.</p> <p>An attacker must have the ability to execute code on a victim system to exploit this vulnerability.</p> <p>After installing this security update, you <em>must</em> manually delete all shadow copies of system files, including the SAM database, to fully mitigate this vulnerabilty. <strong>Simply installing this security update will not fully mitigate this vulnerability.</strong> See <a href="https://support.microsoft.com/topic/1ceaa637-aaa3-4b58-a48b-baf72a2fa9e7">KB5005357- Delete Volume Shadow Copies</a>.</p>

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html
Source: secure@microsoft.com
Third Party Advisory VDB Entry
http://packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Vendor Advisory
https://www.kb.cert.org/vuls/id/506989
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
US Government Resource

6 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.8 / 10.0
EPSS (Exploit Probability)
90.8%
100th percentile
Exploitation Status
Actively Exploited
Remediation due: 2022-02-24

Affected Vendors

microsoft