# KB4523171: November 2019 security update

KB4523171, released November 12, 2019, fixes 1 CVE across 5 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/kb4523171
- Platform: Microsoft
- Released: Nov 12, 2019
- Priority: Urgent (Closes CVE-2019-1373, rated Critical)
- CVEs: 1, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/4523171

## 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) |  |  |
| [Microsoft Exchange Server 2016 Cumulative Update 13](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-2016-cumulative-update-13.md) |  |  |
| [Microsoft Exchange Server 2016 Cumulative Update 14](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-2016-cumulative-update-14.md) |  |  |
| [Microsoft Exchange Server 2019 Cumulative Update 2](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-2019-cumulative-update-2.md) |  |  |
| [Microsoft Exchange Server 2019 Cumulative Update 3](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-2019-cumulative-update-3.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2019-1373](https://patchblox.com/security/data/cve/CVE-2019-1373.md) | Urgent | Microsoft Exchange Server | n/a | 0.2168 |  |

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo