// For flags

CVE-2021-38634

Microsoft Windows Update Client Elevation of Privilege Vulnerability

Severity Score

7.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Microsoft Windows Update Client Elevation of Privilege Vulnerability

Una Vulnerabilidad de ElevaciĆ³n de Privilegios en Microsoft Windows Update Client

This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within Windows Update Agent. By creating a directory junction, an attacker can abuse Windows Update Agent to delete a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM.

*Credits: Abdelhamid Naceri
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-08-13 CVE Reserved
  • 2021-09-15 CVE Published
  • 2023-12-29 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-269: Improper Privilege Management
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
--
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
20h2
Search vendor "Microsoft" for product "Windows 10" and version "20h2"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
21h1
Search vendor "Microsoft" for product "Windows 10" and version "21h1"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
1607
Search vendor "Microsoft" for product "Windows 10" and version "1607"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
1809
Search vendor "Microsoft" for product "Windows 10" and version "1809"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
1909
Search vendor "Microsoft" for product "Windows 10" and version "1909"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows 10
Search vendor "Microsoft" for product "Windows 10"
2004
Search vendor "Microsoft" for product "Windows 10" and version "2004"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows Server 2016
Search vendor "Microsoft" for product "Windows Server 2016"
--
Affected
Microsoft
Search vendor "Microsoft"
Windows Server 2016
Search vendor "Microsoft" for product "Windows Server 2016"
20h2
Search vendor "Microsoft" for product "Windows Server 2016" and version "20h2"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows Server 2016
Search vendor "Microsoft" for product "Windows Server 2016"
2004
Search vendor "Microsoft" for product "Windows Server 2016" and version "2004"
-
Affected
Microsoft
Search vendor "Microsoft"
Windows Server 2019
Search vendor "Microsoft" for product "Windows Server 2019"
--
Affected
Microsoft
Search vendor "Microsoft"
Windows Server 2022
Search vendor "Microsoft" for product "Windows Server 2022"
--
Affected