Exchange Server SE SU10 has been released
Hi All,
Yesterday, Microsoft has released the Exchange SE SU10.
- Exchange Team Blog Released: September 2026 Exchange Server Security Updates
- Description of the security update for Microsoft Exchange Server Subscription Edition RTM: September 8, 2026 (KB5121608)
It fixes the following CVEs
- CVE-2026-55007 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69355 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69356 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69361 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69375 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69378 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69382 - Microsoft Common Vulnerabilities and Exposures
- CVE-2026-69641 - Microsoft Common Vulnerabilities and Exposures
Known issues in this update
Issues resolved in this update
- Wrapper messages appear in shared mailbox in hybrid environments after installing the June 2026 Security Update
- Availability (free/busy) fails for delegated mailboxes in Exchange hybrid deployments using Graph API only
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
There are now some legacy Security Groups that can be deleted
- Exchange Domain Servers
- Exchange Enterprise Servers
- Exchange Recipient Administrators
Happy Exchange patching 😎
Regards
Andres Bohren
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