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Office Online Server OOS Office Online Server Security update
Patch Tuesday

KB5002884

KB5002884: Cumulative update for Office Online Server, version OOS, July 2026. Excel remote code execution and information disclosure flaws fixed

In short

Excel vulnerabilities that could allow remote code execution or expose information are fixed. Office Online Server updates end on December 31, 2026.

Does it affect you? Applies to: Office Online Server (OOS) x64 installations.

Build
16.0.10417.20175
Security
58 fixed · 3 critical
Restart
Required

What changes

Fixes 2 changes

Microsoft Excel

2 items

For: Office Online Server administrators

  • The update fixes Excel flaws that could let attackers run code remotely.1
  • The update fixes Excel flaws that could expose information.1

Technical details

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

Data sheet

Released
2026-07-14
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5002875, KB5002871, KB5002855, KB5002846
+17 earlier KB5002835, KB5002824, KB5002817, KB5002801, KB5002797, KB5002776, KB5002752, KB5002740, KB5002728, KB5002707, KB5002699, KB5002690, KB5002679, KB5002677, KB5002648, KB5002601, KB5002503
Replaced by
KB5002895
VersionBuildChannel
OOS 16.0.10417.20175 General availability

Security

58 vulnerabilities fixed
3 critical 55 important
VulnerabilitySeverityCVSS
CVE-2026-68794
Microsoft Excel Remote Code Execution Vulnerability
 Critical 7.8
CVE-2026-68804
Microsoft Excel Remote Code Execution Vulnerability
 Critical 7.8
CVE-2026-68816
Microsoft Excel Remote Code Execution Vulnerability
 Critical 7.8

The table lists the 3 exploited, publicly disclosed or critical vulnerabilities. See all 58 vulnerabilities →

Downloads (Microsoft Update Catalog)

Package OOS
1.0 GB
wacserver-x-none.cab Main update · KB5002884 SHA-1: cd730520…d23014

Page history

  1. Added CVE-2026-68800 (Important)

    Added CVE-2026-68807 (Important)

  2. Removed CVE-2026-68807

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. This security update resolves Microsoft Excel remote code execution vulnerability and Microsoft Excel Information Disclosure vulnerability. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 1 quoted passage · compared with Microsoft's page on Sep 26, 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: not 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