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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-54121 Active Directory Certificate Services Elevation of Privilege Vulnerability New On this page  CVE-2026-54121  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Jul 14, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-54121  Impact Elevation of Privilege Max Severity Critical Weakness CWE-285: Improper Authorization CVSS Source Microsoft Vector String CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Metrics CVSS:3.1 8.8 / 7.7  Base score metrics: 8.8 / Temporal score metrics: 7.7  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Network Attack Complexity Low Privileges Required Low User Interaction None Scope Unchanged Confidentiality High Integrity High Availability High   Temporal score metrics(3) Exploit Code Maturity Unproven Remediation Level Official Fix Report Confidence Confirmed Please see Common Vulnerability Scoring System for more information on the definition of these metrics. Executive Summary Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed No Exploited No Exploitability assessment Exploitation Less Likely FAQ 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. Acknowledgements Aniq Fakhrul 𝕏 @ aniqfakhrul Aniq Fakhrul 𝕏 @ aniqfakhrul Muhammad Ali 𝕏 @ h0j3n Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgements for more information. Security Updates To determine the support lifecycle for your software, see the Microsoft Support Lifecycle. Release date Descending  Edit columns  Download  Filters  Product Family  Max Severity  Impact  Platform   Clear Release date  Product Platform Impact Max Severity Article Download Build Number Assigning CNA Title: Release date, Content: Jul 14, 2026 Windows Server 2025 (Server Core installation) - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2025 (Server Core installation), Content:, 1 link 5099536  Title: Download Security Update for Windows Server 2025 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.33158 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2022 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2022, Content:, 1 link 5099540  Title: Download Security Update for Windows Server 2022, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.20348.5386 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2019 (Server Core installation) - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2019 (Server Core installation), Content:, 1 link 5099538  Title: Download Security Update for Windows Server 2019 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.9020 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2019 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2019, Content:, 1 link 5099538  Title: Download Security Update for Windows Server 2019, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.9020 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1809 for x64-based Systems - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows 10 Version 1809 for x64-based Systems, Content:, 1 link 5099538  Title: Download Security Update for Windows 10 Version 1809 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.9020 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1809 for 32-bit Systems - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows 10 Version 1809 for 32-bit Systems, Content:, 1 link 5099538  Title: Download Security Update for Windows 10 Version 1809 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.9020 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2012 R2 (Server Core installation) - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2012 R2 (Server Core installation), Content:, 1 link 5099444  Title: Download Security Update for Windows Server 2012 R2 (Server Core installation), Content:, 1 link Monthly Rollup  Title: Build numbers, Content: 6.3.9600.23291 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2012 R2 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2012 R2, Content:, 1 link 5099444  Title: Download Security Update for Windows Server 2012 R2, Content:, 1 link Monthly Rollup  Title: Build numbers, Content: 6.3.9600.23291 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2012 (Server Core installation) - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2012 (Server Core installation), Content:, 1 link 5099445  Title: Download Security Update for Windows Server 2012 (Server Core installation), Content:, 1 link Monthly Rollup  Title: Build numbers, Content: 6.2.9200.26226 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2012 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2012, Content:, 1 link 5099445  Title: Download Security Update for Windows Server 2012, Content:, 1 link Monthly Rollup  Title: Build numbers, Content: 6.2.9200.26226 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2016 (Server Core installation) - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2016 (Server Core installation), Content:, 1 link 5099535  Title: Download Security Update for Windows Server 2016 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2016 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2016, Content:, 1 link 5099535  Title: Download Security Update for Windows Server 2016, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1607 for x64-based Systems - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows 10 Version 1607 for x64-based Systems, Content:, 1 link 5099535  Title: Download Security Update for Windows 10 Version 1607 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1607 for 32-bit Systems - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows 10 Version 1607 for 32-bit Systems, Content:, 1 link 5099535  Title: Download Security Update for Windows 10 Version 1607 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2025 - Elevation of Privilege Critical Title: Knowledge Base Articles for Windows Server 2025, Content:, 1 link 5099536  Title: Download Security Update for Windows Server 2025, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.33158 Title: Assigning CNA, Content: Microsoft All results loaded Loaded all 15 rows Disclaimer The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. 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