CVE-2021-36934 Microsoft Windows SAM Local Privilege Escalation
Attackers with local access can escalate privileges to SYSTEM via permissive ACLs on system files, requiring manual shadow copy deletion after patching.
- Exploited in the wild
- Since 10 Feb 2022
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-36934?
CVE-2021-36934 is a high-severity vulnerability in Microsoft Windows 10 1809, published on 22 Jul 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2021-36934?
It affects 5 products.
Products include Microsoft Windows 10 1809, Microsoft Windows 10 1909, Microsoft Windows 10 2004, Microsoft Windows 10 20h2, Microsoft Windows 10 21h1.
How do I fix CVE-2021-36934?
No fix has been published for CVE-2021-36934 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Feb 2022.
Is CVE-2021-36934 being exploited?
Yes. Attackers have exploited CVE-2021-36934 in the wild since at least 10 Feb 2022.
Public exploit code: 1 Metasploit module and 24 proofs of concept on GitHub.
Other vulnerabilities in Microsoft Windows 10 1809
- CVE-2024-29988 Microsoft SmartScreen Prompt Security Feature Bypass
- CVE-2024-21412 Microsoft Windows Internet Shortcut Files Security Feature Bypass
- CVE-2025-62221 Microsoft Windows Use After Free
- CVE-2025-30400 Microsoft Windows DWM Core Library Use-After-Free
- CVE-2024-21338 Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control
Sources
Also known as GHSA-x4m2-px5g-5q55.