Skip to the content
The Update Bureau
Exchange Server 2019 CU14 Exchange Server 2019 CU14 ESU only Security update
Patch Tuesday

KB5066368

KB5066368: Security update for Exchange Server 2019 CU14, October 2025. Exchange vulnerabilities patched; Auth Certificate export ends

In short

Fixes three Important Exchange Server vulnerabilities and removes Auth Certificate export through an Exchange cmdlet. It is available only to organizations in the Extended Security Update program.

Does it affect you? Applies to: Organizations enrolled in the Extended Security Update program that run Exchange Server 2019 CU14.

Build
15.2.1544.36
Servicing branch
CU14
Security
3 fixed
Review notes Additional details from the official release notes (2) Read notes
  • This page Auth Certificate export through an Exchange cmdlet is no longer supported.
  • In short Auth Certificate export through an Exchange cmdlet is no longer supported.

The official sources are linked at the end of the page.

For servers running Cumulative Update 14: each cumulative update gets its own update. Support for this version ended on October 14, 2025: Microsoft releases this update only to organizations enrolled in the Extended Security Update (ESU) program, not through Microsoft Update. The others should move to Exchange Server Subscription Edition. Which version am I on?

What changes

Fix 1 change

Exchange Server

  • The update fixes three security vulnerabilities in Exchange Server.1
    Addresses CVE-2025-59249 and CVE-2025-53782 (elevation of privilege), and CVE-2025-59248 (spoofing).

Removal 1 change

Exchange cmdlets

  • Auth Certificate export through an Exchange cmdlet is no longer supported.2

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
CU14
Replaces
KB5066371, KB5063222
Replaced by
KB5071874
VersionBuildChannel
2019 15.2.1544.36 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

1,020 files changed since the previous update for the same versions.

Top changed componentsFiles
Management and PowerShell133
Transport93
Client access (POP, IMAP, ActiveSync)33
Mailbox replication33
Search27
Compliance and eDiscovery26
Exchange Web Services and Autodiscover17
Outlook on the web8
Setup8

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. This security update rollup resolves vulnerabilities in Microsoft Exchange Server. support.microsoft.com
  2. 2. Auth Certificate export through Exchange cmdlet is no longer supported support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · 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 4/5, completeness 4/5. 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