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.

From the National Vulnerability Database. This product uses the NVD API but is not endorsed or certified by the NVD.

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56155
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56155