# KB5004778: July 2021 security update

KB5004778, released July 13, 2021, fixes 3 CVEs in Microsoft Exchange Server 2013 Cumulative Update 23. One of them is being exploited (CVE-2021-31196); 1 on CISA KEV. Patch Radar priority: Patch now. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb5004778
- Platform: Microsoft
- Released: Jul 13, 2021
- Priority: Patch now (Closes CVE-2021-31196, exploited (CISA KEV))
- CVEs: 3, exploited: 1, on CISA KEV: 1
- Vendor advisory: https://support.microsoft.com/help/5004778

## 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-2021-31196](https://patchblox.com/security/data/cve/CVE-2021-31196.md) | Patch now | Microsoft Exchange Server | 7.2 | 0.5406 | CISA KEV |
| [CVE-2021-31206](https://patchblox.com/security/data/cve/CVE-2021-31206.md) | High | Microsoft Exchange Server | 7.6 | 0.1301 |  |
| [CVE-2021-34470](https://patchblox.com/security/data/cve/CVE-2021-34470.md) | High | Microsoft Exchange Server | 8.0 | 0.0438 |  |

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo