Description
Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.
Published: 2026-10-13
Score: 7.4 High
EPSS: < 1% Very Low
KEV: No
Impact: Authentication Spoofing
Action: Patch Now
AI Analysis

Impact

The vulnerability arises from weak authentication in Active Directory Federation Services. An attacker over the network can spoof identities, gaining unauthorized access to domain resources. This is an authentication bypass and impersonation flaw identified as CWE‑1390.

Affected Systems

Affected systems include Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809, Windows Server 2012 R2 (including Server Core installation), Windows Server 2016 (including Server Core installation), Windows Server 2019 (including Server Core installation), Windows Server 2022, Windows Server 2025 (including Server Core installation).

Risk and Exploitability

The CVSS score of 7.4 indicates a high severity impact. The EPSS score is not available, but the lack of a CISA KEV listing does not reduce the importance of a patch. The likely attack vector is network-based and requires an unauthenticated attacker to send crafted authentication requests to the AD FS service, potentially enabling impersonation and lateral movement within a domain.

Generated by OpenCVE AI on October 14, 2026 at 03:47 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the Microsoft security update that fixes CVE-2026-83511
  • Configure AD FS to use only secure authentication methods, such as MFA or certificate‑based authentication
  • Restrict or disable legacy authentication protocols that may be vulnerable to spoofing

Generated by OpenCVE AI on October 14, 2026 at 03:47 UTC.

Tracking

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Advisories

No advisories yet.

History

Wed, 28 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows Server 2012
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*
Vendors & Products Microsoft windows Server 2012

Sun, 18 Oct 2026 05:45:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Vendors & Products Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)

Wed, 14 Oct 2026 05:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Tue, 13 Oct 2026 19:15:00 +0000

Type Values Removed Values Added
Description Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.
Title Active Directory Federation Services (AD FS) Spoofing Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Weaknesses CWE-1390
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
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:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C'}

Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows Server 2012 Windows Server 2012 R2 Windows Server 2012 R2 Windows Server 2012 R2 (server Core Installation) Windows Server 2016 Windows Server 2016 (server Core Installation) Windows Server 2019 Windows Server 2019 (server Core Installation) Windows Server 2022 Windows Server 2025 Windows Server 2025 (server Core Installation)
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-10-31T18:08:19.259Z

Reserved: 2026-08-31T15:57:21.154Z

Link: CVE-2026-83511

cve-icon Vulnrichment

Updated: 2026-10-13T22:19:06.868Z

cve-icon NVD

Status : Analyzed

Published: 2026-10-13T19:19:56.460

Modified: 2026-10-28T18:15:22.017

Link: CVE-2026-83511

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-18T05:30:16Z

Weaknesses