# KB4593466: December 2020 security update

KB4593466, released December 8, 2020, fixes 4 CVEs in Microsoft Exchange Server 2013 Cumulative Update 23. 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/kb4593466
- Platform: Microsoft
- Released: Dec 8, 2020
- Priority: Urgent (Closes CVE-2020-17132, rated Critical)
- CVEs: 4, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/4593466

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft Exchange Server 2013 Cumulative Update 23](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-2013-cumulative-update-23.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-17132](https://patchblox.com/security/data/cve/CVE-2020-17132.md) | Urgent | Microsoft Exchange Server | 9.1 | 0.8990 |  |
| [CVE-2020-17117](https://patchblox.com/security/data/cve/CVE-2020-17117.md) | Urgent | Microsoft Exchange Server | 6.6 | 0.4887 |  |
| [CVE-2020-17142](https://patchblox.com/security/data/cve/CVE-2020-17142.md) | Urgent | Microsoft Exchange Server | 9.1 | 0.0337 |  |
| [CVE-2020-17143](https://patchblox.com/security/data/cve/CVE-2020-17143.md) | High | Microsoft Exchange Server | 8.8 | 0.7063 |  |

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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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo