Active Directory Federation Services Elevation of Privilege Vulnerability

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Summary

CVECVE-2026-56155
StatePUBLISHED
Assignermicrosoft
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-14 17:17:09 UTC
Updated2026-07-15 14:18:24 UTC
DescriptionInsufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003790000 probability, percentile 0.301190000 (date 2026-07-15)

CISA KEV: Listed on 2026-07-14; due 2026-07-28; ransomware use Unknown

Problem Types: CWE-1220 | CWE-1220 CWE-1220: Insufficient Granularity of Access Control

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNACVSS7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA Known Exploited Vulnerability

VendorMicrosoft
ProductActive Directory Federation Services
NameMicrosoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability
Required ActionApply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Noteshttps://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56155 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-56155; https://learn.microsoft.com/en-us/windows-server/identity/ad-fs/decommission/adfs-decommission-guide

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Microsoft Windows 10 1607 All All All All
Operating System Microsoft Windows 10 1607 All All All All
Operating System Microsoft Windows 10 1809 All All All All
Operating System Microsoft Windows 10 1809 All All All All
Operating System Microsoft Windows Server 2012 - All All All
Operating System Microsoft Windows Server 2012 r2 All All All
Operating System Microsoft Windows Server 2016 All All All All
Operating System Microsoft Windows Server 2019 All All All All
Operating System Microsoft Windows Server 2022 All All All All
Operating System Microsoft Windows Server 2025 All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Microsoft Windows 10 Version 1607 affected 10.0.14393.0 10.0.14393.9339 custom 32-bit Systems, x64-based Systems
CNA Microsoft Windows 10 Version 1809 affected 10.0.17763.0 10.0.17763.9020 custom 32-bit Systems, x64-based Systems
CNA Microsoft Windows Server 2012 affected 6.2.9200.0 6.2.9200.26226 custom x64-based Systems
CNA Microsoft Windows Server 2012 Server Core Installation affected 6.2.9200.0 6.2.9200.26226 custom x64-based Systems
CNA Microsoft Windows Server 2012 R2 affected 6.3.9600.0 6.3.9600.23291 custom x64-based Systems
CNA Microsoft Windows Server 2012 R2 Server Core Installation affected 6.3.9600.0 6.3.9600.23291 custom x64-based Systems
CNA Microsoft Windows Server 2016 affected 10.0.14393.0 10.0.14393.9339 custom x64-based Systems
CNA Microsoft Windows Server 2016 Server Core Installation affected 10.0.14393.0 10.0.14393.9339 custom x64-based Systems
CNA Microsoft Windows Server 2019 affected 10.0.17763.0 10.0.17763.9020 custom x64-based Systems
CNA Microsoft Windows Server 2019 Server Core Installation affected 10.0.17763.0 10.0.17763.9020 custom x64-based Systems
CNA Microsoft Windows Server 2022 affected 10.0.20348.0 10.0.20348.5386 custom x64-based Systems
CNA Microsoft Windows Server 2025 affected 10.0.26100.0 10.0.26100.33158 custom x64-based Systems
CNA Microsoft Windows Server 2025 Server Core Installation affected 10.0.26100.0 10.0.26100.33158 custom x64-based Systems

References

ReferenceSourceLinkTags
www.cisa.gov/known-exploited-vulnerabilities-catalog 134c704f-9b21-4f2e-91b3-4a467353bcc0 www.cisa.gov US Government Resource
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56155 [email protected] msrc.microsoft.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
CISA Known Exploited Vulnerabilities catalog CISA www.cisa.gov kev
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