CVE-2026-56155 | defend.network

What is CVE-2026-56155?

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

CVSS7.8 NVD 3.1

SeverityHIGH

Exploitation In the wild In CISA KEV

EPSS<1% · P26

Triage statusActive Exploit

ActionPatch immediately

CVSS vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWECWE-1220

NVD published2026-07-14

NVD last modified2026-07-15

Timeline

2026-07-14Published to the U.S. National Vulnerability Database (NVD)
2026-07-14Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
2026-07-15NVD record last updated
2026-07-16First covered in a defend.network daily briefing
2026-07-28CISA federal remediation deadline (BOD 22-01)

CISA Known Exploited Vulnerability

Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

Added to KEV2026-07-14

Federal patch deadline2026-07-28

Known ransomware useUnknown

Affected product

Microsoft Active Directory Federation Services

NVD also lists CPE entries for: Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019

Remediation Steps

Apply the vendor security update for Microsoft Windows 10 1607 as a priority.
Restrict network exposure of the affected service to trusted sources until patched.
Review logs and detections for indicators of exploitation.
Confirm fixed versions against the official vendor advisory before deploying.

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 2 of August 2026 (August 10 – 16)
Vulnerability Priority Report – Week 1 of August 2026 (August 3 – 9)
Vulnerability Priority Report – Week 4 of July 2026 (July 27 – August 2)
Vulnerability Priority Report – Week 3 of July 2026 (July 20 – 26)
Vulnerability Priority Report – Week 2 of July 2026 (July 13 – 19)
Scattered Spider sentenced; Microsoft patches record 570 flaws; macOS ClickLock stealer active (2026-07-17)
Microsoft SharePoint, Windows zero-days actively exploited; Zoom account takeover critical (2026-07-16)

Browse all tracked CVEs in the defend.network CVE database →

🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.