How severe is CVE-2026-56155?

CVE-2026-56155 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56155 being actively exploited?

Yes. CVE-2026-56155 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-07-14, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-56155?

CVE-2026-56155 primarily affects Microsoft Windows 10 1607. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-56155?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

When was CVE-2026-56155 published?

CVE-2026-56155 was published on 2026-07-14 and last updated on 2026-07-15.

CVE-2026-56155

CVE-2026-56155 is a high-severity vulnerability in Microsoft Windows 10 1607 with a CVSS 3.x base score of 7.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-07-14). The underlying weakness is classified as CWE-1220.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-07-14)
Weakness: CWE-1220
Affected product: Microsoft Windows 10 1607
Published: 2026-07-14
Last modified: 2026-07-15

Description

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

Frequently asked questions

What is CVE-2026-56155?: Insufficient granularity of access control in Active Directory Federation Services (AD FS) allows an authorized attacker to elevate privileges locally.
How severe is CVE-2026-56155?: CVE-2026-56155 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56155 being actively exploited?: Yes. CVE-2026-56155 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-07-14, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-56155?: CVE-2026-56155 primarily affects Microsoft Windows 10 1607. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-56155?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
When was CVE-2026-56155 published?: CVE-2026-56155 was published on 2026-07-14 and last updated on 2026-07-15.

References

Affected products (10)

cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

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