# CVE-2026-97801: .NET Framework Tampering Vulnerability CVE-2026-97801 is fixed in 27 products on 1 platform, first by KB5126868, released October 13, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-97801 - Priority: High - CVSS: 7.5 (Important) - EPSS: 0.0073 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Vendor exploitability assessment: Exploitation Less Likely - Published: Oct 13, 2026 - Weakness: Improper Validation of Specified Type of Input - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97801 ## Description

Improper validation of specified type of input in .NET Framework allows an unauthorized attacker to perform tampering over a network.

## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 version 1607 | 14393.9612 | [KB5126868](https://patchblox.com/security/data/fix/microsoft/kb5126868.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 | 14393.9612 | [KB5126868](https://patchblox.com/security/data/fix/microsoft/kb5126868.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019 | | [KB5127666](https://patchblox.com/security/data/fix/microsoft/kb5127666.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 version 1809 | | [KB5127666](https://patchblox.com/security/data/fix/microsoft/kb5127666.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 1809 | | [KB5127685](https://patchblox.com/security/data/fix/microsoft/kb5127685.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 21H2 | | [KB5127683](https://patchblox.com/security/data/fix/microsoft/kb5127683.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 22H2 | | [KB5127683](https://patchblox.com/security/data/fix/microsoft/kb5127683.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 | | [KB5127685](https://patchblox.com/security/data/fix/microsoft/kb5127685.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022 | | [KB5127687](https://patchblox.com/security/data/fix/microsoft/kb5127687.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 21H2 | | [KB5127689](https://patchblox.com/security/data/fix/microsoft/kb5127689.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 22H2 | | [KB5127689](https://patchblox.com/security/data/fix/microsoft/kb5127689.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 23H2 | | [KB5127692](https://patchblox.com/security/data/fix/microsoft/kb5127692.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 24H2 | | [KB5127690](https://patchblox.com/security/data/fix/microsoft/kb5127690.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 25H2 | | [KB5127690](https://patchblox.com/security/data/fix/microsoft/kb5127690.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 26H2 | | [KB5127694](https://patchblox.com/security/data/fix/microsoft/kb5127694.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022 | | [KB5127693](https://patchblox.com/security/data/fix/microsoft/kb5127693.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025 | | [KB5127690](https://patchblox.com/security/data/fix/microsoft/kb5127690.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 on Windows 11 version 26H1 | | [KB5127696](https://patchblox.com/security/data/fix/microsoft/kb5127696.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 on Windows Server 2012 | | [KB5127660](https://patchblox.com/security/data/fix/microsoft/kb5127660.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 3.5 on Windows Server 2012 R2 | | [KB5127664](https://patchblox.com/security/data/fix/microsoft/kb5127664.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 | | [KB5127667](https://patchblox.com/security/data/fix/microsoft/kb5127667.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 | | [KB5127668](https://patchblox.com/security/data/fix/microsoft/kb5127668.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.8 on Windows 10 version 1607 | | [KB5127684](https://patchblox.com/security/data/fix/microsoft/kb5127684.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.8 on Windows Server 2012 | | [KB5127686](https://patchblox.com/security/data/fix/microsoft/kb5127686.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.8 on Windows Server 2012 R2 | | [KB5127688](https://patchblox.com/security/data/fix/microsoft/kb5127688.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.8 on Windows Server 2016 | | [KB5127684](https://patchblox.com/security/data/fix/microsoft/kb5127684.md) | Oct 13, 2026 | | Microsoft | Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1 | | [KB5127691](https://patchblox.com/security/data/fix/microsoft/kb5127691.md) | Oct 13, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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