CVE-2026-56155: Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

CISA Known Exploited Vulnerabilities

Name

Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

Vendor

Microsoft

Product

Active Directory Federation Services

Added to the catalog

2026-07-14

Due date for US federal agencies

2026-07-28

Weaknesses

CWE-1220

Catalog version

2026.10.30

Microsoft Active Directory Federation Services contains an insufficient granularity of access control vulnerability that allows an authorized attacker to elevate privileges locally.

Required action (CISA)

Apply 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.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56155
• https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• 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

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2026-07-14T17:17:09.763

Last modified

2026-07-15T14:18:24.010

Weaknesses

CWE-1220

Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56155 (Vendor Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56155 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:31.494Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-56155

CVE record

Title (CNA)

Active Directory Federation Services Elevation of Privilege Vulnerability

Assigner

microsoft

State

PUBLISHED

Published

2026-07-14T17:05:11.702Z

Updated

2026-11-01T17:32:48.789Z

Problem types

CWE-1220: Insufficient Granularity of Access Control

References

• Active Directory Federation Services Elevation of Privilege Vulnerability

Read on 2026-11-03T02:20:37.262Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/56xxx/CVE-2026-56155.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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