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Microsoft · Active Directory Federation Services

CVE-2026-56155

Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

CISA KEV record

CISA date added
2026-07-14
CISA due date
2026-07-28
Known ransomware use
Unknown

NVD risk context

7.8 HIGH

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

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Attack vector
Local
An attacker needs local access to the affected system.
Attack complexity
Low
Exploitation does not require unusual conditions beyond normal attacker control.
Privileges required
Low
The attacker needs limited privileges before exploiting the issue.
User interaction
None
No action by another user is required.

Description

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

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.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

Other NVD references (1)

MITRE CWE context

CWE classification

CWE-1220 Insufficient Granularity of Access Control

The product implements access controls via a policy or other feature with the intention to disable or restrict accesses (reads and/or writes) to assets in a system from untrusted agents. However, implemented access controls lack required granularity, which renders the control policy too broad because it allows accesses from unauthorized agents to the security-sensitive assets.

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NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published
Jul 14, 2026, 05:17 PM UTC
When NVD first published this CVE record.
NVD last updated
Jul 15, 2026, 02:18 PM UTC
When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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CISA notes

https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56155 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-56155; https://learn.microsoft.com/en-us/windows-server/identity/ad-fs/decommission/adfs-decommission-guide