Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.

CheckOps priority index

4.3/10 Patch within 7 days

Severity7.8

Probability0.0

Exploitation2/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 0.35% higher than 28.2% of CVEs

CVSS 3.1 7.8 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:

Exploited for 112 days 14 Jul 2026

CISA due date 28 Jul 2026 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 2 / 5

KEV catalog (CISA)14 Jul 2026
Exploited in EUVD (ENISA)14 Jul 2026
Used by ransomwareno
EPSS above 10 %0.35%
No account, over the networkno

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: 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.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Windows 10 Version 1809Windows Server 2019Windows Server 2012 (Server Core installation)Windows Server 2012 R2 (Server Core installation)Windows Server 2016Windows Server 2012Windows Server 2022Windows Server 2025Windows Server 2019 (Server Core installation)Windows Server 2016 (Server Core installation)Windows 10 Version 1607Windows Server 2025 (Server Core installation)Windows Server 2012 R2Active Directory Federation Services

Affected versions

10.0.17763.0 <10.0.17763.9020
6.2.9200.0 <6.2.9200.26226
6.3.9600.0 <6.3.9600.23291
10.0.14393.0 <10.0.14393.9339
10.0.20348.0 <10.0.20348.5386
10.0.26100.0 <10.0.26100.33158

Weaknesses (CWE)

CWE-1220

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

14 Jul 2026
Published
14 Jul 2026
Exploitation reported (ENISA)
14 Jul 2026
Added to the KEV catalog
28 Jul 2026
CISA remediation due date

References

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