CVE-2026-56155: high-severity vulnerability in Microsoft Windows 10 Version 1607
Active Directory Federation Services Elevation of Privilege Vulnerability
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
Prioritize patching. It under exploitation confirmed by CISA and has an official Brazilian government alert.
Brazil's federal government published an alert, recommendation or bulletin that cites this vulnerability.
- CISC Gov.br · 21 Jul 2026Boletim do CISC de Vulnerabilidaderead on gov.br ↗
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.
Active Directory Federation Services has a flaw in how it controls who can do what, allowing someone with basic access to gain higher privileges on the system. This is serious because attackers could take over administrative functions.
Insufficient access control granularity in AD FS permits an authenticated attacker to escalate privileges through local exploitation. The vulnerability requires prior authorization but lacks proper permission boundaries, enabling lateral privilege elevation within the federation infrastructure.
The full analysis of this CVE is available in Portuguese →
In the same product, most dangerous first.