Exchange Server SE SU11 has been released
Hi All,
Yesterday, Microsoft has released the Exchange SE SU11.
- Exchange Team Blog Released: October 2026 Exchange Server Security Updates
- Description of the security update for Microsoft Exchange Server Subscription Edition RTM October 13, 2026 (KB5128895)
It fixes the following CVEs
- CVE-2026-70571 - Microsoft Exchange Server Remote Code Execution Vulnerability
- CVE-2026-77910 - Microsoft Exchange Server Elevation of Privilege Vulnerability
- CVE-2026-87692 - Microsoft Exchange Server Elevation of Privilege Vulnerability
- CVE-2026-87695 - Microsoft Exchange Server Elevation of Privilege Vulnerability
- CVE-2026-87696 - Microsoft Exchange Server Elevation of Privilege Vulnerability
- CVE-2026-70279 - Microsoft Exchange Server Spoofing Vulnerability
Issues resolved in this update
- Published calendar (.ics) returns HTTP 500 for calendar applications
- ContentEngine deadlock because of missing Korean WordBreaker rule files
The Process is simple: Install the SU and the run the Exchange Health Checker
You can download the Security Update here:
Installation
Bevore starting the Installation, i check if there is a pending reboot with a PowerShell Script i’ve wrote
.\Check-PendingReboot.ps1
After a reboot everything looks fine
.\Check-PendingReboot.ps1
Let’s start the Installation
The Installation of the Security Update has successfully completed
Check the Version
Get-Command Exsetup.exe | ForEach-Object {$_.FileVersionInfo}
Check for Pending reboot
.\Check-PendingReboot.ps1
Healthchecker
Microsoft recommends to run the HealthChecker after each Installation. The HealthChecker can be downloaded here:
In the first run, the HealthChecker updates the Script
.\HealthChecker.ps1
Now we can run the HealthChecker - nothing worring was found
.\HealthChecker.ps1
Old OWA / ECP Directorys
From time to time, i go and delete the old OWA and ECP Directorys. Sadly they are still not removed by any Exchange SU or CU
C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\Owa
C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\ecp
Happy Exchange patching 😎
Regards
Andres Bohren
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