Skip to the content
The Update Bureau
Exchange Server Subscription Edition RTM Exchange Server Subscription Edition RTM Security update
Patch Tuesday

KB5066366

KB5066366: Security update for Exchange Server Subscription Edition RTM, October 2025. Auth Certificate export via cmdlet no longer supported

In short

The update addresses three Important vulnerabilities in Exchange Server. It also notes that Auth Certificate export through the Exchange cmdlet is no longer supported.

Does it affect you? Applies to: Exchange Server Subscription Edition RTM, including x64 installations. The update installs build 15.2.2562.29.

Build
15.2.2562.29
Servicing branch
RTM
Security
3 fixed
Restart
Required

What changes

Fix 1 change

Auth Certificate export

  • Auth Certificate export through the Exchange cmdlet is no longer supported.1

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2025-10-14
Classification
Security Updates
Type
Cumulative update
Servicing branch
RTM
Restart
Required
Replaces
KB5066373, KB5063224
Replaced by
KB5071876
VersionBuildChannel
SE 15.2.2562.29 General availability

Security

3 vulnerabilities fixed
3 important
VulnerabilitySeverityCVSS
CVE-2025-59249
Microsoft Exchange Server Elevation of Privilege Vulnerability
 Important 8.8
CVE-2025-53782
Microsoft Exchange Server Elevation of Privilege Vulnerability
 Important 8.4
CVE-2025-59248
Microsoft Exchange Server Spoofing Vulnerability
 Important 7.5

Updated components

590 files changed since the previous update for the same versions.

Top changed componentsFiles
Transport75
Management and PowerShell41
Mailbox replication28
Client access (POP, IMAP, ActiveSync)27
Compliance and eDiscovery23
Search23
Exchange Web Services and Autodiscover12
Setup7
Outlook on the web5

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. Auth Certificate export through Exchange cmdlet is no longer supported support.microsoft.com
Checked automatically: 8 of 8 checks passed, 1 quoted passage · compared with Microsoft's page on Oct 20, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 4/5, clarity 5/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake