# KB4579977: October 2020 security update

KB4579977, released October 13, 2020, fixes 2 CVEs across 11 products. One of them is being exploited (CVE-2020-1147); 1 on CISA KEV. Patch Radar priority: Patch now. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb4579977
- Platform: Microsoft
- Released: Oct 13, 2020
- Priority: Patch now (Closes CVE-2020-1147, exploited (CISA KEV))
- CVEs: 2, exploited: 1, on CISA KEV: 1
- Vendor advisory: https://support.microsoft.com/help/4579977

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft .NET Framework 3.5.1 on Windows 7 for 32-bit Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-3.5.1-on-windows-7-for-32-bit-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 3.5.1 on Windows 7 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-3.5.1-on-windows-7-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-3.5.1-on-windows-server-2008-r2-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows 7 for 32-bit Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-7-for-32-bit-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows 7 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-7-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-server-2008-r2-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.5.2-on-windows-server-2008-r2-for-x64-based-systems-service-pack-1-server-core-installation.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows 7 for 32-bit Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-7-for-32-bit-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows 7 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-7-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-server-2008-r2-for-x64-based-systems-service-pack-1.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-server-2008-r2-for-x64-based-systems-service-pack-1-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-1147](https://patchblox.com/security/data/cve/CVE-2020-1147.md) | Patch now | .NET Framework | 8.8 | 0.9580 | CISA KEV |
| [CVE-2020-16937](https://patchblox.com/security/data/cve/CVE-2020-16937.md) | Routine | .NET Framework | 4.7 | 0.0329 | Disclosed |

---

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