# CVE-2026-56155

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

- Page: https://www.vulneraibility.com/cve/CVE-2026-56155
- CVSS: 7.8
- Known exploited: yes, in CISA KEV since 2026-07-14; CISA due date 2026-07-28
- EPSS: 0.35%
- CISA SSVC: exploitation active, automatable no, technical impact total (assessed 2026-07-15)
- Weakness: CWE-1220
- Published: 2026-07-14

## Affected versions

- Microsoft Windows 10 Version 1607: affected >= 10.0.14393.0 and < 10.0.14393.9339
- Microsoft Windows 10 Version 1809: affected >= 10.0.17763.0 and < 10.0.17763.9020
- Microsoft Windows Server 2012: affected >= 6.2.9200.0 and < 6.2.9200.26226
- Microsoft Windows Server 2012 R2: affected >= 6.3.9600.0 and < 6.3.9600.23291
- Microsoft Windows Server 2012 R2 (Server Core installation): affected >= 6.3.9600.0 and < 6.3.9600.23291
- Microsoft Windows Server 2012 (Server Core installation): affected >= 6.2.9200.0 and < 6.2.9200.26226
- Microsoft Windows Server 2016: affected >= 10.0.14393.0 and < 10.0.14393.9339
- Microsoft Windows Server 2016 (Server Core installation): affected >= 10.0.14393.0 and < 10.0.14393.9339
- Microsoft Windows Server 2019: affected >= 10.0.17763.0 and < 10.0.17763.9020
- Microsoft Windows Server 2019 (Server Core installation): affected >= 10.0.17763.0 and < 10.0.17763.9020
- Microsoft Windows Server 2022: affected >= 10.0.20348.0 and < 10.0.20348.5386
- Microsoft Windows Server 2025: affected >= 10.0.26100.0 and < 10.0.26100.33158
- Microsoft Windows Server 2025 (Server Core installation): affected >= 10.0.26100.0 and < 10.0.26100.33158

A version outside these ranges is not a statement that it is unaffected.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56155
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56155

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.