Weak authentication in AD FS allows network spoofing
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Active Directory Federation Services (AD FS) in Microsoft Windows 10 Version 1607 and 1809 and Windows Server 2016, 2019, 2022 and 2025 is affected. Weak authentication (CWE-1390) lets an unauthorized remote attacker perform spoofing over the network, with high attack complexity.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 to before 10.0.14393.9612 | 10.0.14393.9612 | Patch available | CNA |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 to before 10.0.17763.9376 | 10.0.17763.9376 | Patch available | CNA |
| Microsoft | Windows Server 2016 | 10.0.14393.0 to before 10.0.14393.9612 | 10.0.14393.9612 | Patch available | CNA |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 to before 10.0.14393.9612 | 10.0.14393.9612 | Patch available | CNA |
| Microsoft | Windows Server 2019 | 10.0.17763.0 to before 10.0.17763.9376 | 10.0.17763.9376 | Patch available | CNA |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 to before 10.0.17763.9376 | 10.0.17763.9376 | Patch available | CNA |
| Microsoft | Windows Server 2022 | 10.0.20348.0 to before 10.0.20348.5761 | 10.0.20348.5761 | Patch available | CNA |
| Microsoft | Windows Server 2025 | 10.0.26100.0 to before 10.0.26100.33650 | 10.0.26100.33650 | Patch available | CNA |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 to before 10.0.26100.33650 | 10.0.26100.33650 | Patch available | CNA |
- Windows 10 Version 1607 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.9612 Fixed in 10.0.14393.9612 Patch available CNA
- Windows 10 Version 1809 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
- Windows Server 2016 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.9612 Fixed in 10.0.14393.9612 Patch available CNA
- Windows Server 2016 (Server Core installation) VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.9612 Fixed in 10.0.14393.9612 Patch available CNA
- Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
- Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
- Windows Server 2022 VendorMicrosoft Affected 10.0.20348.0 to before 10.0.20348.5761 Fixed in 10.0.20348.5761 Patch available CNA
- Windows Server 2025 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA
- Windows Server 2025 (Server Core installation) VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* | before 10.0.14393.9612 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* | before 10.0.14393.9612 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* | before 10.0.17763.9376 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* | before 10.0.17763.9376 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* | before 10.0.14393.9612 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* | before 10.0.17763.9376 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:* | before 10.0.20348.5761 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* | before 10.0.26100.33650 | Vulnerable | Microsoft |
- cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* Versions before 10.0.14393.9612 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* Versions before 10.0.14393.9612 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* Versions before 10.0.17763.9376 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* Versions before 10.0.17763.9376 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* Versions before 10.0.14393.9612 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* Versions before 10.0.17763.9376 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:* Versions before 10.0.20348.5761 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* Versions before 10.0.26100.33650 Vulnerable ·Microsoft
Remediation
Install the fixed versions for each product: Windows 10 Version 1607 and Windows Server 2016 (including Server Core installation) 10.0.14393.9612; Windows 10 Version 1809 and Windows Server 2019 (including Server Core installation) 10.0.17763.9376; Windows Server 2022 10.0.20348.5761; Windows Server 2025 (including Server Core installation) 10.0.26100.33650.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
- Fix · CNA Windows 10 Version 1607 (Microsoft) Fixed in 10.0.14393.9612
- Fix · CNA Windows 10 Version 1809 (Microsoft) Fixed in 10.0.17763.9376
- Fix · CNA Windows Server 2016 (Microsoft) Fixed in 10.0.14393.9612
- Fix · CNA Windows Server 2016 (Server Core installation) (Microsoft) Fixed in 10.0.14393.9612
- Fix · CNA Windows Server 2019 (Microsoft) Fixed in 10.0.17763.9376
- Fix · CNA Windows Server 2019 (Server Core installation) (Microsoft) Fixed in 10.0.17763.9376
- Fix · CNA Windows Server 2022 (Microsoft) Fixed in 10.0.20348.5761
- Fix · CNA Windows Server 2025 (Microsoft) Fixed in 10.0.26100.33650
- Fix · CNA Windows Server 2025 (Server Core installation) (Microsoft) Fixed in 10.0.26100.33650
Timeline
- 2026-10-13 Threatist record created from CVE-2026-83674
- 2026-10-13 Alias added: GHSA-f3fh-9v4g-62gx
- 2026-10-14 CISA SSVC decision points changed
- 2026-10-14 Priority changed: MEDIUM → LOW
- 2026-10-14 CISA SSVC decision points changed
- 2026-10-21 EPSS moved to the 50th–90th percentile
References
More Microsoft Windows 10 1607 vulnerabilities
- TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2017-06077 Microsoft Windows XP SP3, Windows XP x64 XP2, Windows Server 2003 SP2, Windows Vista… KEVCVSS 3.1CRITICAL 9.8
- TI-2026-73128 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2026-17367 MSHTML Framework Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2026-17364 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2025-24062 Windows SMB Client Elevation of Privilege Vulnerability KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2026-83674 · CVE Program
- CVE-2026-83674 · NVD
- FIRST EPSS
- GHSA-f3fh-9v4g-62gx · GitHub Advisory Database · CC BY 4.0
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