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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-56155 Active Directory Federation Services Elevation of Privilege Vulnerability New On this page  CVE-2026-56155  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Jul 14, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-56155  Impact Elevation of Privilege Max Severity Important Weakness CWE-1220: Insufficient Granularity of Access Control CVSS Source Microsoft Vector String CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C Metrics CVSS:3.1 7.8 / 7.2  Base score metrics: 7.8 / Temporal score metrics: 7.2  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Local Attack Complexity Low Privileges Required Low User Interaction None Scope Unchanged Confidentiality High Integrity High Availability High   Temporal score metrics(3) Exploit Code Maturity Functional Remediation Level Official Fix Report Confidence Confirmed Please see Common Vulnerability Scoring System for more information on the definition of these metrics. Executive Summary Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed No Exploited Yes Exploitability assessment Exploitation Detected 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. Acknowledgements Jeremy Kingston (DART) with Microsoft Scott Clark (DART) with Microsoft 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 2012 R2 (Server Core installation) - Elevation of Privilege Important 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 Important 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 Important 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 Important 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 Important 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 Important 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 Important 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 Important 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 Important 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 Title: Release date, Content: Jul 14, 2026 Windows Server 2025 (Server Core installation) - Elevation of Privilege Important 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 Important 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 Important 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 Important 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 Important 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 Important 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 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. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Revisions version revisionDate description 1.0 Jul 14, 2026 Information published.  How satisfied are you with the MSRC Security Update Guide? Rating  Broken  Bad  Below average  Average  Great!  Your Privacy Choices Consumer Health Privacy Privacy & Cookies