Patch tracker / CVE reference / CVE-2026-40366
CVE-2026-40366
CVE-2026-40366 is a high severity Microsoft vulnerability with a CVSS score of 8.4. Microsoft has shipped the fix: deploy the update below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Risk summary
Not in the CISA KEV catalog. EPSS exploit probability 4.4%. CVSS 8.4 (High).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
Another Word parsing flaw from the same batch as CVE-2026-40364, with the same shape: Office 2019 and Microsoft 365 Apps affected, code execution when a crafted document is opened, EPSS at 4 percent. Attackers rarely need more than one working document exploit, so paired fixes like these should ship together.
Do this: Deploy the full Office security update rather than cherry-picking individual Word fixes.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-40366
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Official patch(es) for CVE-2026-40366
Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing update KB5002858 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security update below to fix CVE-2026-40366. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.
Scope and sources
- Affected products
- Fixed by the same update
- Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.