CVE-2025-53786
HighCVSS 8.0Exploitation Probability (EPSS)
Very high risk94th percentile - higher than 94% of all known CVEs
Summary
On April 18th, 2025, Microsoft announced security changes for Exchange Server in hybrid deployments and accompanying hot fixes. Further investigation revealed specific security implications related to these changes.
Risk Assessment
Failure to follow the guidance may lead to significant security vulnerabilities in hybrid Exchange environments, exposing the organization to attacks.
Recommendation
It is recommended to review the information in the April 18th announcement, install the April 2025 (or later) hot fix, and implement the necessary changes in the Exchange Server.
Original NVD description (English source)
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.