CVE-2026-96222: Microsoft .net Framework 3.5

High severity, CVSS 7.4. EPSS: 0.6% chance of exploitation in the next 30 days.

Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

Affected products

• Microsoft Microsoft .net Framework 3.5
• Microsoft Microsoft .net Framework 3.5 And 4.6.2/4.7/4.7.1/4.7.2
• Microsoft Microsoft .net Framework 3.5 And 4.7.2
• Microsoft Microsoft .net Framework 3.5 And 4.8
• Microsoft Microsoft .net Framework 3.5 And 4.8.1
• Microsoft Microsoft .net Framework 4.6.2/4.7/4.7.1/4.7.2: from 4.7.0, before 4.7.4150.0 (fixed in 4.7.4150.0)
• Microsoft Microsoft .net Framework 4.8: from 4.8.0, before 4.8.4811.0 (fixed in 4.8.4811.0)
• Microsoft Microsoft .net Framework 4.8.1: from 4.8.0.0, before 4.8.9363.0 (fixed in 4.8.9363.0)
• Microsoft Microsoft Visual Studio 2022 Version 17.14: from 17.14.0, before 17.14.42 (fixed in 17.14.42)
• Microsoft Microsoft Visual Studio 2026 Version 18.10: from 18.10.0, before 18.10.4 (fixed in 18.10.4)
• Microsoft System.security.cryptography.xml: from 10.0.0, before 8.0.5 (fixed in 8.0.5)
• Microsoft Windows 10 Version 1607: from 10.0.14393.0, before 10.0.14393.9612 (fixed in 10.0.14393.9612)
• Microsoft Windows 10 Version 1809: from 10.0.17763.0, before 10.0.17763.9376 (fixed in 10.0.17763.9376)
• Microsoft Windows Server 2012 r2: from 6.3.9600.0, before 6.3.9600.23470 (fixed in 6.3.9600.23470)
• Microsoft Windows Server 2012 r2 Server Core Installation: from 6.3.9600.0, before 6.3.9600.23470 (fixed in 6.3.9600.23470)
• Microsoft Windows Server 2016: from 10.0.14393.0, before 10.0.14393.9612 (fixed in 10.0.14393.9612)
• Microsoft Windows Server 2016 Server Core Installation: from 10.0.14393.0, before 10.0.14393.9612 (fixed in 10.0.14393.9612)
• Microsoft Windows Server 2019: from 10.0.17763.0, before 10.0.17763.9376 (fixed in 10.0.17763.9376)
• Microsoft Windows Server 2019 Server Core Installation: from 10.0.17763.0, before 10.0.17763.9376 (fixed in 10.0.17763.9376)
• Microsoft Windows Server 2022: from 10.0.20348.0, before 10.0.20348.5761 (fixed in 10.0.20348.5761)
• Microsoft Windows Server 2025: from 10.0.26100.0, before 10.0.26100.33650 (fixed in 10.0.26100.33650)
• Microsoft Windows Server 2025 Server Core Installation: from 10.0.26100.0, before 10.0.26100.33650 (fixed in 10.0.26100.33650)

Affected packages

• System.Security.Cryptography.Xml (NuGet)

Published 2026-10-13. Last modified 2026-10-14.