MSRXCVE-2026-56155
CVE-2026-56155
Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability
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.
CVSS 3.1 · CNA · microsoft.com
chance of exploitation in the next 30 days (EPSS; higher than 28% of CVEs)
Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.
Scores
Affected products
- microsoft windows 10 1607: < 10.0.14393.9339
- microsoft windows 10 1809: < 10.0.17763.9020
- microsoft windows server 2012: all versions; r2
- microsoft windows server 2016: < 10.0.14393.9339
- microsoft windows server 2019: < 10.0.17763.9020
- microsoft windows server 2022: < 10.0.20348.5386
- microsoft windows server 2025: < 10.0.26100.33158
Weakness: CWE-1220
2 references (advisories, patches, write-ups)
- 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
Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.