CVE-2025-53786: Microsoft Exchange Server

High severity, CVSS 8.0. EPSS: 7.7% chance of exploitation in the next 30 days.

On April 18th 2025, Microsoft announced Exchange Server Security Changes for Hybrid Deployments and accompanying non-security Hot Fix. Microsoft made these changes in the general interest of improving the security of hybrid Exchange deployments. Following further investigation, Microsoft identified specific security implications tied to the guidance and configuration steps outlined in the April announcement. Microsoft is issuing CVE-2025-53786 to document a vulnerability that is addressed by taking the steps documented with the April 18th announcement. Microsoft strongly recommends reading the information, installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.

Affected products

• Microsoft Exchange Server: version 2016 only; version 2019 only
• Microsoft Exchange Server Subscription Edition: before 15.02.2562.017 (fixed in 15.02.2562.017)

Published 2025-08-06. Last modified 2026-06-17.