Original article content
This security update rollup resolves vulnerabilities in Microsoft Exchange Server. To learn more about these vulnerabilities, see the following Common Vulnerabilities and Exposures (CVE)
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CVE-2025-59249Â - Microsoft Exchange Server Elevation of Privilege Vulnerability
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CVE-2025-53782Â - Microsoft Exchange Server Elevation of Privilege Vulnerability
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CVE-2025-59248 - Microsoft Exchange Server Spoofing Vulnerability​​​​​​​​​​​​​​
Note:Â Please follow the instructions in the Microsoft Security Response Center (MSRC) article to address the vulnerability.
Issues that are fixed in this updateÂ
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Auth Certificate export through Exchange cmdlet is no longer supported​​​​​​​
Exchange Server Health CheckerÂ
To verify that that the installation is successful, and check whether any additional actions are required, run the Exchange Server Exchange Server Health Checker.
Enabling Extended Protection in Exchange Server
To enable Extended Protection on Exchange-based servers, see Extended Protection enabled in Exchange Server (KB5017260).
How to get and install the update
Microsoft Download Center
You can get the standalone update package through the Microsoft Download Center.
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Microsoft Exchange Server 2016Â Cumulative Update 23Â SU19-Â Download the package now
More information
Security update deployment information
For deployment information about this update, see Deployments - Security Update Guide.
Security update replacement information
This security update replaces the following previously released updates:
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​​​​​​​Hotfix update for Exchange Server 2016 CU23 HU18: September 8, 2025 (KB5066370)
File information
File hash information
|
Update Name |
File name |
SHA256 hash |
|---|---|---|
|
Exchange Server 2016Â Cumulative Update 23Â SU19 |
Exchange2016-KB5066369-x64-en.exe |
2232F8D633FAF4EF5563F21A6E894D4450E7B82292CE6B801498E19125307F21 |
Hashes for additional languages
The hash tables for additional languages are available here:
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Hash tables for Exchange Server 2016 CU23 SU19 (KB5066367) - Download the hashes now
Exchange Server file information
The English (United States) version of this update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). The dates and times for these files on your local computer are displayed in your local time together with your current daylight-saving time (DST) bias. Additionally, the dates and times may change when you perform certain operations on the files.
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Microsoft Exchange Server 2016Â Cumulative Update 23Â SU19Â -Download the worksheet now
More information
For more information about the deployment of Exchange Server SE, see Release notes for Exchange Server SE.​​​​​​​ For more information about the coexistence of Exchange Server SE and earlier versions of Exchange Server in the same environment, see Exchange Server SE system requirements. For more information about other Exchange updates, see Exchange Server Updates: Build numbers and release dates.
Information about protection and security
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