CVE-2021-36934
Windows Elevation of Privilege Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Windows Elevation of Privilege Vulnerability
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.
- Record
CVE-2021-36934- CVSS 3.1
- 7.8 High
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 - Updated
- 2026-11-02
EUVDEUVD-2021-23510
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.
- Record
EUVD-2021-23510- CVSS 3.1
- 7.8 High
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-x4m2-px5g-5q55
Windows Elevation of Privilege Vulnerability
Windows Elevation of Privilege Vulnerability
- Record
GHSA-x4m2-px5g-5q55- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-269, CWE-732
- Updated
- 2026-11-02
CISA KEV No score
Microsoft Windows SAM Local Privilege Escalation Vulnerability
If a Volume Shadow Copy (VSS) shadow copy of the system drive is available, users can read the SAM file which would allow any user to escalate privileges to SYSTEM level.
- Record
CVE-2021-36934- Weakness
- CWE-1220
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-36934- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 4.6 Medium
AV:L/AC:L/Au:N/C:P/I:P/A:P - Updated
- 2026-11-02
Affected products
- microsoft windows
- microsoft windows 10 version 1809
- microsoft windows 10 version 1909
- microsoft windows 10 version 2004
- microsoft windows 10 version 20h2
- microsoft windows 10 version 21h1
- microsoft windows 10 1809
- microsoft windows 10 1909
- microsoft windows 10 2004
- microsoft windows 10 20h2
- microsoft windows 10 21h1
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | HuskyHacks/ShadowSteal | 2021-07-20 |
| PoC in GitHub | JoranSlingerland/CVE-2021-36934 | 2021-07-21 |
| PoC in GitHub | n3tsurge/CVE-2021-36934 | 2021-07-21 |
| PoC in GitHub | VertigoRay/CVE-2021-36934 | 2021-07-22 |
| PoC in GitHub | Wh04m1001/VSSCopy | 2021-07-22 |
| PoC in GitHub | WiredPulse/Invoke-HiveDreams | 2021-07-22 |
| PoC in GitHub | WiredPulse/Invoke-HiveNightmare | 2021-07-22 |
| PoC in GitHub | bytesizedalex/CVE-2021-36934 | 2021-07-22 |
| PoC in GitHub | romarroca/SeriousSam | 2021-07-22 |
| PoC in GitHub | tda90/CVE-2021-36934 | 2021-07-22 |
Show 15 moreShow less
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | Preventions/CVE-2021-36934 | 2021-07-24 |
| PoC in GitHub | Sp00kySkelet0n/PyNightmare | 2021-07-25 |
| PoC in GitHub | jmaddington/Serious-Sam---CVE-2021-36934-Mitigation-for-Datto-RMM | 2021-07-25 |
| PoC in GitHub | 0x0D1n/CVE-2021-36934 | 2021-07-26 |
| PoC in GitHub | exploitblizzard/CVE-2021-36934 | 2021-07-27 |
| PoC in GitHub | irissentinel/CVE-2021-36934 | 2021-07-29 |
| PoC in GitHub | websecnl/CVE-2021-36934 | 2021-08-01 |
| PoC in GitHub | grishinpv/poc_CVE-2021-36934 | 2021-08-02 |
| PoC in GitHub | shaktavist/SeriousSam | 2021-08-04 |
| PoC in GitHub | OlivierLaflamme/CVE-2021-36934-export-shadow-volume-POC | 2021-08-10 |
| PoC in GitHub | chron1k/oxide_hive | 2021-08-12 |
| PoC in GitHub | P1rat3R00t/Why-so-Serious-SAM | 2025-06-09 |
| PoC in GitHub | d4yon/CVE-2021-36934-HiveNightmare-Lab | 2026-02-22 |
| PoC in GitHub | DuyDuongDuyDuong/CVE-2021-36934-DLL-Hijacking-DFIR-Investigation | 2026-08-15 |
| Metasploit | Windows SAM secrets leak - HiveNightmare | 2021-07-20 |
History
| Recorded | Changed | Sources |
|---|---|---|
| exploitation | ||
| exploits | ||
| exploits | ||
| first indexed | CVE List, EUVD, GitHub Advisories, CISA KEV, Metasploit, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-36934 is a high vulnerability (CVSS 7.8) in Microsoft Windows, published July 22, 2021. CISA lists it as known to be exploited, since February 10, 2022. EUVD reports exploitation since February 10, 2022. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 67.3%, the 99th percentile. No source names a fixed version.
References
msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934
kb.cert.org/vuls/id/506989
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934
packetstormsecurity.com/files/164006/HiveNightmare-AKA-SeriousSAM.html
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934
nvd.nist.gov/vuln/detail/CVE-2021-36934
github.com/advisories/GHSA-x4m2-px5g-5q55