CVE-2026-96222: Active Directory Federation Services (AD FS) Spoofing Vulnerability
Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.
- Published by source
- 2026-10-13
- First seen by Reality Radar
- 2026-10-22
- Last verified
- 2026-10-22
Affected
- Manufacturer
- Microsoft
- Products
- System.Security.Cryptography.Xml on .NET 8.0 installed on Windows System.Security.Cryptography.Xml on .NET 8.0 installed on Linux System.Security.Cryptography.Xml on .NET 8.0 installed on Mac OS Windows 10 Version 1809 Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows 10 Version 1607 Windows Server 2016 Windows Server 2012 R2 Microsoft Visual Studio 2026 version 18.10 Microsoft Visual Studio 2022 version 17.14 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 21H2 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 22H2 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 24H2 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 25H2 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025 Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 23H2 Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022
- CPE
- cpe:2.3:a:microsoft:system.security.cryptography.xml:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
Whether your exact unit is affected depends on the model, serial number and region in the official notice.
What the official notice says
Risk: Critical — Spoofing
Remedy / actions:
- Install the security update: https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5126651
Is this affecting you?
Add what you own or use and Reality Radar will tell you when official changes match it — with evidence and next steps.
Sources
- Microsoft Security Update Guide (MSRC) Tier A · official published 2026-10-13
Evidence ledger
Every piece of evidence we store is appended to a public hash chain, so later edits are detectable. Anyone can re-verify it.
| Entry | Kind | Observed | Evidence hash | Entry hash |
|---|---|---|---|---|
| #167 | new | 2026-10-22 | 551ccd9f7f28…3e3c6d | 0b8e026c2466…8b71bd |
Chain head: #1076 8ad5adc30b9b…88ce20