Risk Letters

Exploited vulnerability

CVE-2026-56155

TLP:CLEAR

Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

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

Facts

  • Vendor: Microsoft
  • Product: Active Directory Federation Services
  • CVSS: 7.8
  • EPSS (probability of exploitation within 30 days): 0.3 %
  • On CISA's Known Exploited Vulnerabilities list since: 14 July 2026
  • First known exploitation: 14 July 2026
  • CISA's deadline for US federal agencies: 28 July 2026
  • Weakness: CWE-1220
  • First seen by Risk Letters: 14 July 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD