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Office Online Server OOS Office Online Server Security update
Patch Tuesday

KB5002776

KB5002776: Cumulative update for Office Online Server, version OOS, September 2025. Excel remote code execution vulnerability resolved

In short

The update resolves an Excel remote code execution vulnerability and fixes six Important vulnerabilities in total. Office Online Server updates end on December 31, 2026.

Does it affect you? Applies to: Servers running the release version of Office Online Server. The update package is for x64 systems.

Build
16.0.10417.20047
Security
6 fixed
Restart
Required

What changes

Fix 1 change

Excel

Verified in package

For: Office Online Server administrators

  • The update resolves a Microsoft Excel remote code execution vulnerability.1

Technical details

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

Data sheet

Released
2025-09-09
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5002752, KB5002740, KB5002728, KB5002707
+7 earlier KB5002699, KB5002690, KB5002679, KB5002677, KB5002648, KB5002601, KB5002503
Replaced by
KB5002797
VersionBuildChannel
OOS 16.0.10417.20047 General availability

Security

6 vulnerabilities fixed
6 important
VulnerabilitySeverityCVSS
CVE-2025-54896
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-54898
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-54900
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-54902
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-54903
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8
CVE-2025-54904
Microsoft Excel Remote Code Execution Vulnerability
 Important 7.8

Downloads (Microsoft Update Catalog)

Package OOS
1.0 GB
wacserver-x-none.cab Main update · KB5002776 SHA-1: 371fba82…c50842

Updated components

1,597 files changed since the previous update for the same versions.

Top changed componentsFiles
Office web apps368
PowerPoint324
Excel261
Document conversion74
Word50

Verified in package: changed files confirm Excel.

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. This security update resolves a 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 4/5, 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