Patch tracker / KB5002928
KB5002928: Office Online Server Security Update (October 2026)
KB5002928 is a High security update for Office Online Server, released 2026-10-13. It closes 44 CVEs with a maximum CVSS of 8.8. It is the 11th largest of the 68 updates Microsoft shipped that month, by CVEs closed.
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Update summary
Fixes 44 CVEs. Most severe CVSS 8.8 (High). EPSS exploit probability up to <1%. Among the lower half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Office Online Server has shipped since this one: KB5002946 (2026-11-10). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.
We checked Microsoft's support article for KB5002928 on 2026-11-09 and it lists no known issues. Read the article before broad deployment; Microsoft adds issues as reports come in, and we re-check on every refresh.
KB5002928 is the October 2026 security update for Office Online Server, fixing 44 CVEs with a highest Severity of High (CVSS 8.8). None of the fixes are in the CISA KEV catalog or linked to ransomware, and the highest EPSS is only 1%, so this is a large batch of vulnerabilities rather than a response to known exploitation. Exposure is limited to organizations that self-host Office Online Server, typically to serve document viewing and editing for SharePoint, Exchange, or Skype for Business, and those servers are often reachable from user networks or the internet.
Do this: Schedule KB5002928 on your Office Online Server farm this patch cycle, starting with any server reachable from outside the corporate network, and confirm the farm is healthy afterward.
AI-generated from public data, 2026-11-10. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5002928
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5002928
- Released
- 2026-10-13
- Last changed
- 2026-10-15
- Changes tracked
- 3
Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.
Check if KB5002928 is installed
This update is for Office Online Server, not a Windows component, so Get-HotFix does not list it. Compare the installed version of the product with the build Microsoft lists for this update.
CVEs fixed by this update
Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.
Scope and sources
- Affected products
- Also released in October 2026
KB5126646
1097 CVEs · Critical · exploitedKB5126651
973 CVEs · Critical · exploitedKB5126653
1021 CVEs · Critical · exploitedKB5126655
1033 CVEs · Critical · exploitedKB5126657
954 CVEs · Critical · exploitedKB5126836
666 CVEs · Critical · exploitedKB5126868
785 CVEs · Critical · exploitedKB5127646
1055 CVEs · Critical · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.