# CVE-2023-35388: Microsoft Exchange Server Remote Code Execution Vulnerability

CVE-2023-35388 is fixed in 3 products on 1 platform, first by KB5030524, released September 12, 2023. It is not reported as exploited, but the vendor rates exploitation more likely. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2023-35388
- Priority: Urgent
- CVSS: 8.0 (Important)
- EPSS: 0.0685
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation More Likely
- Published: Aug 9, 2023
- Weakness: Deserialization of Untrusted Data
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-35388

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 |  | [KB5030524](https://patchblox.com/security/data/fix/microsoft/kb5030524.md) | Sep 12, 2023 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 12 |  | [KB5030524](https://patchblox.com/security/data/fix/microsoft/kb5030524.md) | Sep 12, 2023 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 13 |  | [KB5030524](https://patchblox.com/security/data/fix/microsoft/kb5030524.md) | Sep 12, 2023 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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