CVE-2025-53786

Microsoft Exchange Server Hybrid Deployment Elevation of Privilege Vulnerability

CVE-2025-53786 is fixed in 4 products on 1 platform, first by KB5050674, released August 12, 2025. It is not reported as exploited, but the vendor rates exploitation more likely. Patch Radar priority: Urgent.

Urgent
CVSS
8.0
Important
Exploitation
More likely
Vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0803
94th percentile

<p>On April 18th 2025, Microsoft announced <a href="https://techcommunity.microsoft.com/blog/exchange/exchange-server-security-changes-for-hybrid-deployments/4396833">Exchange Server Security Changes for Hybrid Deployments</a> and accompanying non-security <a href="https://techcommunity.microsoft.com/blog/exchange/released-april-2025-exchange-server-hotfix-updates/4402471">Hot Fix</a>. 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.</p>

Where it's fixed

ProductFixed inFixReleased
Microsoft
Microsoft Exchange Server 2016 Cumulative Update 23 KB5050674 Aug 12, 2025
Microsoft Exchange Server 2019 Cumulative Update 14 KB5050673 Aug 12, 2025
Microsoft Exchange Server 2019 Cumulative Update 15 KB5050672 Aug 12, 2025
Microsoft Exchange Server Subscription Edition RTM KB5047155 Aug 12, 2025

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