# CVE-2025-59248: Microsoft Exchange Server Spoofing Vulnerability

CVE-2025-59248 is fixed in 4 products on 1 platform, first by KB5066369, released October 14, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-59248
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0102
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Oct 14, 2025
- Weakness: Improper Input Validation
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59248

## Description

<p>Improper input validation in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 |  | [KB5066369](https://patchblox.com/security/data/fix/microsoft/kb5066369.md) | Oct 14, 2025 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 14 |  | [KB5066368](https://patchblox.com/security/data/fix/microsoft/kb5066368.md) | Oct 14, 2025 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 15 |  | [KB5066367](https://patchblox.com/security/data/fix/microsoft/kb5066367.md) | Oct 14, 2025 |
| Microsoft | Microsoft Exchange Server Subscription Edition RTM |  | [KB5066366](https://patchblox.com/security/data/fix/microsoft/kb5066366.md) | Oct 14, 2025 |

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Data as of 2026-11-08T19:12:23Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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