Summary
Impact: Elevation of Privilege. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
What privileges could be gained by an attacker who successfully exploited the vulnerability?
An attacker who successfully exploited this vulnerability could gain administrator privileges.
How could an attacker exploit this vulnerability?
An authenticated attacker could manipulate attributes associated with a machine account and obtain a certificate from Active Directory Certificate Services that allows authentication as that machine via PKINIT. If a Domain Controller account can be targeted, the attacker could authenticate as the Domain Controller and gain the ability to perform privileged Active Directory operations.
Security updates
10.0.17763.9020 — https://support.microsoft.com/help/5099538
10.0.20348.5386 — https://support.microsoft.com/help/5099540
10.0.26100.33158 — https://support.microsoft.com/help/5099536
10.0.14393.9339 — https://support.microsoft.com/help/5099535
6.2.9200.26226 — https://support.microsoft.com/help/5099445
6.3.9600.23291 — https://support.microsoft.com/help/5099444
Vulnerabilities 1
-
High 8.8CVE-2026-54121 Public exploit
Active Directory Certificate Services Elevation of Privilege Vulnerability
Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
Revision history
-
#1
Information published.
References
-
CVE-2026-54121 Active Directory Certificate Services Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54121
-
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
-
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
-
Common Vulnerability Scoring System
https://www.first.org/cvss