Exploited vulnerability · CISA KEV

Is CVE-2026-56155 exploited? Yes: in CISA KEV since 14 Jul 2026

Gociux · Microsoft Active Directory Federation Services · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2026-56155, Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability , is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 14 Jul 2026, the day it was published. It affects Microsoft Active Directory Federation Services. If you run it, CISA's required action is: 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.

What it is

Microsoft Active Directory Federation Services contains an insufficient granularity of access control vulnerability that allows an authorized attacker to elevate privileges locally.

What to do

1. Check whether you run it. Look for Active Directory Federation Services in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
2. Apply the fix. 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.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 14 Jul 2026.
4. Get told next time. Email alerts when CISA adds a CVE for Microsoft.

References

• msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56155
• nvd.nist.gov/vuln/detail/CVE-2026-56155
• learn.microsoft.com/en-us/windows-server/identity/ad-fs/decommission/adfs-decom

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in July 2026 · Microsoft scorecard · act-now radar.