CVE-2026-56155ImportantExploitedCISA KEV · due 28 Jul
Active Directory Federation Services Elevation of Privilege Vulnerability
Listed in the CISA Known Exploited Vulnerabilities catalog
Added 14 Jul 2026 · federal remediation due 28 Jul 2026.
Microsoft Active Directory Federation Services contains an insufficient granularity of access control vulnerability that allows an authorized attacker to elevate privileges locally.
Assessment
Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.
- Severity
- Important
- CVSS base score
- 7.8CVSS:3.1/
AV:L/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:F/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- 0.3%Higher than 25.6% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
- Exploitability
- Exploitation detected
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Active Directory Federation Services (AD FS)
- Weakness
- CWE-1220: Insufficient Granularity of Access Control
- Issued by
- Microsoft
- Published
- 14 Jul 2026 · July 2026
- Last revised
- 14 Jul 2026
Updates that fix it
6 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5099444 | Monthly Rollup | Required | Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) | All CVEs in KB5099444 |
| KB5099445 | Monthly Rollup | Required | Windows Server 2012, Windows Server 2012 (Server Core installation) | All CVEs in KB5099445 |
| KB5099535 | Security Update | Required | Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems, Windows Server 2016 and 1 more | All CVEs in KB5099535 |
| KB5099536 | Security Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | All CVEs in KB5099536 |
| KB5099538 | Security Update | Required | Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 1 more | All CVEs in KB5099538 |
| KB5099540 | Security Update | Required | Windows Server 2022 | All CVEs in KB5099540 |
Affected products
ESU, Windows15 affected products
- Windows 10 Version 1607 for 32-bit Systems
- Windows 10 Version 1607 for x64-based Systems
- Windows 10 Version 1809 for 32-bit Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows Server 2012
- Windows Server 2012 (Server Core installation)
- Windows Server 2012 R2
- Windows Server 2012 R2 (Server Core installation)
- Windows Server 2016
- Windows Server 2016 (Server Core installation)
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2025
- Windows Server 2025 (Server Core installation)