Patch tracker / KB5002866
KB5002866: Microsoft Office 2019 for 32-bit editi Security Update (May 2026)
KB5002866 is a High security update for Microsoft Office 2019 for 32-bit editi, released 2026-05-12. It closes 2 CVEs with a maximum CVSS of 8.4. It is the 21st largest of the 61 updates Microsoft shipped that month, by CVEs closed.
Update summary
Fixes 2 CVEs. Most severe CVSS 8.4 (High). EPSS exploit probability up to <1%. Among the lower half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Microsoft Office 2019 for 32-bit editions has shipped since this one: KB5002755 (2026-08-11). 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 KB5002866 on 2026-08-07 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.
KB5002866 patches two vulnerabilities in Microsoft Office 2019 (32-bit and 64-bit) and Microsoft 365 Apps for Enterprise (32-bit), with the more serious flaw rated High at CVSS 8.4. Exposure is broad since Office is on most business desktops, but exploitation probability is currently low: EPSS sits at 0 percent and neither CVE-2026-40363 nor CVE-2026-40358 is in the CISA KEV catalog or linked to ransomware. This is a routine Patch Tuesday Office update from 2026-05-12 rather than an emergency, so schedule it into your normal cycle.
Do this: Approve KB5002866 for deployment to all Office 2019 and Microsoft 365 Apps for Enterprise machines through your standard update ring this cycle.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5002866
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5002866
- Released
- 2026-05-12
- Last changed
- 2026-05-12
- Changes tracked
- 1
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 KB5002866 is installed
Elevated PowerShell. No output means it is not installed.
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.
| CVE | Severity | CVSS | EPSS | Exploited |
|---|---|---|---|---|
| CVE-2026-40358 | High | 8.4 | <1% | No |
| CVE-2026-40363 | High | 8.4 | <1% | No |
Scope and sources
- Affected products
- Also released in May 2026
KB5002863
9 CVEs · High · exploitedKB5002868
9 CVEs · High · exploitedKB5002870
9 CVEs · High · exploitedKB5094139
1 CVE · High · exploitedKB5094140
1 CVE · High · exploitedKB5094142
1 CVE · High · exploitedKB5094144
1 CVE · High · exploitedKB5078943
3 CVEs · CriticalThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.