ACTIVELY EXPLOITED

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

Facts
VendorMicrosoft
ProductActive Directory Federation Services
Actively exploitedYes
Added to CISA KEV14 Jul 2026
CISA federal deadline28 Jul 2026
Weakness (CWE)CWE-1220

Required action (CISA's text)

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.

Description (NVD)

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

SOURCES

Other Microsoft flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.