CVE-2021-36934

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.

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934Patch, Vendor Advisory
• 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

Published

Jul 22, 2021

Last Modified

Aug 10, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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