Vulnerability in Microsoft Windows 10 1607
CVE-2026-56155
Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.
EPSS: 0.003 (27.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Microsoft Windows_10_1607
- Microsoft Windows_10_1809
- Microsoft Windows 10 Version 1607 — versions 10.0.14393.0
- Microsoft Windows 10 Version 1809 — versions 10.0.17763.0
- Microsoft Windows Server 2012 — versions 6.2.9200.0
- Microsoft Windows_server_2012 — versions r2
- Microsoft Windows Server 2012 R2 — versions 6.3.9600.0
- Microsoft Windows Server 2012 R2 (Server Core Installation) — versions 6.3.9600.0
- Microsoft Windows Server 2012 (Server Core Installation) — versions 6.2.9200.0
- Microsoft Windows Server 2016 — versions 10.0.14393.0
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: 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.
References
- Active Directory Federation Services Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-56155?
- CVE-2026-56155 is a high-severity vulnerability in Microsoft Windows 10 1607, classified under CWE-1220. CVSS score: 7.8/10. Published 2026-07-14.
- How severe is CVE-2026-56155?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2026-56155 known to be exploited?
- Yes. CVE-2026-56155 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-07-14), indicating it is being actively exploited.