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Fencer Vulns
high 7.8

CVE-2026-56155 kev in the critical feed json

Active Directory Federation Services Elevation of Privilege Vulnerability

published 2026-07-14 3 mo ago modified 2026-11-01 7 d ago also EUVD-2026-44042

cvss
7.8
version 3.1, CNA
cisa kev
Exploited
added 2026-07-14
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

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

Patch / fix

cisa 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.

  • Microsoft Windows 10 Version 1607 10.0.14393.9339
  • Microsoft Windows 10 Version 1809 10.0.17763.9020
  • Microsoft Windows Server 2012 6.2.9200.26226
  • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.26226
  • Microsoft Windows Server 2012 R2 6.3.9600.23291
  • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.23291
  • Microsoft Windows Server 2016 10.0.14393.9339
  • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.9339
  • Microsoft Windows Server 2019 10.0.17763.9020
  • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.9020
  • Microsoft Windows Server 2022 10.0.20348.5386
  • Microsoft Windows Server 2025 10.0.26100.33158
  • Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.33158

Timeline

  1. 0-day patched (Project Zero)
  2. Added to CISA KEV
  3. Published
  4. CISA SSVC: exploitation active
  5. CISA patch deadline

Known exploited

Added
3 mo ago
Patch by
2026-07-28 (3 mo ago)
Ransomware
Not known
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.
Vendor, product
Microsoft, Active Directory Federation Services
CISA name
Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Patched
2026-07-14
Details
project zero tracker

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Microsoft Windows 10 Version 1607
  • Microsoft Windows 10 Version 1809
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 (Server Core installation)
  • Microsoft Windows Server 2012 R2
  • Microsoft Windows Server 2012 R2 (Server Core installation)
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2016 (Server Core installation)
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2019 (Server Core installation)
  • Microsoft Windows Server 2022
  • Microsoft Windows Server 2025
  • Microsoft Windows Server 2025 (Server Core installation)

Classification

Weakness
  • CWE-1220 Insufficient Granularity of Access Control

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.