# Microsoft Exchange Server 2016 Cumulative Update 23 security updates

Patch Radar has 24 security fixes for Microsoft Exchange Server 2016 Cumulative Update 23, closing 87 CVEs, 5 of which are being exploited. The newest security fix is KB5128898, released October 13, 2026.

- Web page: https://patchblox.com/security/product/microsoft/microsoft-exchange-server-2016-cumulative-update-23
- Platform: Microsoft
- Vendor: Microsoft
- Supported: yes

## Security fixes, newest first

| Fix | Released | Fixed in | Priority | CVEs | Exploited |
|---|---|---|---|---:|---:|
| [KB5128898](https://patchblox.com/security/data/fix/microsoft/kb5128898.md) | Oct 13, 2026 |  | Urgent | 6 | 0 |
| [KB5129958](https://patchblox.com/security/data/fix/microsoft/kb5129958.md) | Oct 2, 2026 |  | Urgent | 1 | 0 |
| [KB5121611](https://patchblox.com/security/data/fix/microsoft/kb5121611.md) | Sep 8, 2026 |  | High | 8 | 0 |
| [KB5121576](https://patchblox.com/security/data/fix/microsoft/kb5121576.md) | Aug 11, 2026 |  | Urgent | 7 | 0 |
| [KB5103215](https://patchblox.com/security/data/fix/microsoft/kb5103215.md) | Jun 9, 2026 |  | Urgent | 11 | 0 |
| [KB5074995](https://patchblox.com/security/data/fix/microsoft/kb5074995.md) | Feb 10, 2026 |  | Routine | 1 | 0 |
| [KB5071873](https://patchblox.com/security/data/fix/microsoft/kb5071873.md) | Dec 9, 2025 |  | High | 2 | 0 |
| [KB5066369](https://patchblox.com/security/data/fix/microsoft/kb5066369.md) | Oct 14, 2025 |  | High | 3 | 0 |
| [KB5050674](https://patchblox.com/security/data/fix/microsoft/kb5050674.md) | Aug 12, 2025 |  | Urgent | 1 | 0 |
| [KB5063223](https://patchblox.com/security/data/fix/microsoft/kb5063223.md) | Aug 12, 2025 |  | High | 4 | 0 |
| [KB5049233](https://patchblox.com/security/data/fix/microsoft/kb5049233.md) | Nov 12, 2024 |  | Urgent | 1 | 0 |
| [KB5037224](https://patchblox.com/security/data/fix/microsoft/kb5037224.md) | Mar 12, 2024 |  | High | 1 | 0 |
| [KB5036386](https://patchblox.com/security/data/fix/microsoft/kb5036386.md) | Feb 14, 2024 |  | Patch now | 1 | 1 |
| [KB5032147](https://patchblox.com/security/data/fix/microsoft/kb5032147.md) | Nov 14, 2023 |  | Urgent | 4 | 0 |
| [KB5030877](https://patchblox.com/security/data/fix/microsoft/kb5030877.md) | Oct 10, 2023 |  | Urgent | 1 | 0 |
| [KB5030524](https://patchblox.com/security/data/fix/microsoft/kb5030524.md) | Sep 12, 2023 |  | Urgent | 11 | 0 |
| [KB5025903](https://patchblox.com/security/data/fix/microsoft/kb5025903.md) | Jun 13, 2023 |  | Urgent | 2 | 0 |
| [KB5023038](https://patchblox.com/security/data/fix/microsoft/kb5023038.md) | Feb 14, 2023 |  | Patch now | 3 | 1 |
| [KB5024296](https://patchblox.com/security/data/fix/microsoft/kb5024296.md) | Feb 14, 2023 |  | Urgent | 1 | 0 |
| [KB5022143](https://patchblox.com/security/data/fix/microsoft/kb5022143.md) | Jan 10, 2023 |  | Urgent | 5 | 0 |
| [KB5019758](https://patchblox.com/security/data/fix/microsoft/kb5019758.md) | Nov 8, 2022 |  | Patch now | 6 | 3 |
| [KB5019077](https://patchblox.com/security/data/fix/microsoft/kb5019077.md) | Aug 9, 2022 |  | Urgent | 5 | 0 |
| [KB5015322](https://patchblox.com/security/data/fix/microsoft/kb5015322.md) | Aug 9, 2022 |  | Routine | 1 | 0 |
| [KB5014261](https://patchblox.com/security/data/fix/microsoft/kb5014261.md) | May 10, 2022 |  | High | 1 | 0 |

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Data as of 2026-11-12T01:51:14Z 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

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