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Office Online Server OOS Office Online Server Security update
Patch Tuesday

KB5002817

KB5002817: Cumulative update for Office Online Server, version OOS, December 2025. Excel remote code execution flaws resolved

In short

The update resolves five Important-severity Microsoft Excel remote code execution vulnerabilities.

Does it affect you? Applies to: Computers running the release version of Office Online Server.

Build
16.0.10417.20075
Security
5 fixed
Restart
Required

What changes

Fix 1 change

Microsoft Excel

Verified in package

For: Office Online Server users

  • Microsoft Excel remote code execution vulnerabilities are resolved.1
    The update addresses CVE-2025-62556, CVE-2025-62564, CVE-2025-62563, CVE-2025-62561, and CVE-2025-62560.

Technical details

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

Data sheet

Released
2025-12-09
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5002801, KB5002797, KB5002776, KB5002752
+10 earlier KB5002740, KB5002728, KB5002707, KB5002699, KB5002690, KB5002679, KB5002677, KB5002648, KB5002601, KB5002503
Replaced by
KB5002824
VersionBuildChannel
OOS 16.0.10417.20075 General availability

Security

5 vulnerabilities fixed
5 important
VulnerabilitySeverityCVSS
CVE-2025-62556
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-62560
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-62561
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-62563
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-62564
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8

Downloads (Microsoft Update Catalog)

Package OOS
1.0 GB
wacserver-x-none.cab Main update · KB5002817 SHA-1: 7e7094d6…17459d

Updated components

1,592 files changed since the previous update for the same versions.

Top changed componentsFiles
Office web apps369
PowerPoint324
Excel261
Document conversion74
Word50

Verified in package: changed files confirm Microsoft Excel.

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. This security update resolves Microsoft Excel Remote Code Execution vulnerability. 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 5/5, 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