# KB4556406: May 2020 security update

KB4556406, released May 14, 2020, fixes 3 CVEs across 8 products. None of them is reported as exploited. Patch Radar priority: Urgent. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb4556406
- Platform: Microsoft
- Released: May 14, 2020
- Priority: Urgent (Closes CVE-2020-0605, rated Critical)
- CVEs: 3, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/4556406

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-2.0-service-pack-2-on-windows-server-2008-for-32-bit-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-2.0-service-pack-2-on-windows-server-2008-for-x64-based-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-3.0-service-pack-2-on-windows-server-2008-for-32-bit-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-3.0-service-pack-2-on-windows-server-2008-for-x64-based-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows Server 2008 for 32-bit Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-server-2008-for-32-bit-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows Server 2008 for x64-based Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-server-2008-for-x64-based-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 4.6 on Windows Server 2008 for 32-bit Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.6-on-windows-server-2008-for-32-bit-systems-service-pack-2.md) |  |  |
| [Microsoft .NET Framework 4.6 on Windows Server 2008 for x64-based Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.6-on-windows-server-2008-for-x64-based-systems-service-pack-2.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-0605](https://patchblox.com/security/data/cve/CVE-2020-0605.md) | Urgent | .NET Framework | n/a | 0.1840 |  |
| [CVE-2020-1108](https://patchblox.com/security/data/cve/CVE-2020-1108.md) | High | .NET Core | 7.5 | 0.0646 |  |
| [CVE-2020-1066](https://patchblox.com/security/data/cve/CVE-2020-1066.md) | High | .NET Framework | n/a | 0.0252 |  |

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Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo