CVE-2026-56155

Actively exploited

CISA lists CVE-2026-56155 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Microsoft Active Directory Federation Services.

• 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.

Public exploit: Not collected. Review the linked vendor advisory and apply the mitigation or fixed release for your affected product.

• Microsoft Security Response Center: Exploitation reported by Microsoft Security Response Center (2026-07-14)