Patch tracker / CVE reference / CVE-2026-40358
CVE-2026-40358
CVE-2026-40358 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.
High severity Microsoft vulnerability, CVSS 8.4. Fixed by 1 Microsoft security update.
Risk summary
Updated July 26, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2026-40358
CVE-2026-40358 is a High severity (CVSS 8.4) remote code execution flaw in Microsoft Office 2019 and Microsoft 365 Apps for Enterprise, meaning a crafted document could run attacker code with the user's privileges. Exposure is broad because these are standard productivity apps on most Windows endpoints, but the EPSS score is 0% and it is not listed in CISA KEV or tied to ransomware yet. The gap between the high impact rating and the currently low exploitation signal is what makes this a patch-on-schedule item rather than an emergency.
Do this: Deploy the Microsoft Office 2019 and Microsoft 365 Apps for Enterprise security update to all affected 32-bit and 64-bit endpoints through your normal patch cycle.
AI-generated from public data, 2026-07-23. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-40358
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-40358
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
Exploitation and severity
Not in the CISA KEV catalog. EPSS exploit probability <1%. CVSS 8.4 (High).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2026-40358
Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing update KB5002866 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-2026-40358. 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.
Affected products
Common questions about CVE-2026-40358
Is CVE-2026-40358 actively exploited?
It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the next 30 days at <1%.
What patch fixes CVE-2026-40358?
Microsoft fixed CVE-2026-40358 in KB5002866. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2026-40358?
Microsoft 365 Apps for Enterprise for 32-bit Systems, Microsoft Office 2019 for 32-bit editions, Microsoft Office 2019 for 64-bit editions.
Can I ask my own AI about CVE-2026-40358?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-40358's key facts: severity, CVSS, EPSS exploit probability, CISA KEV status, and the fixing KB. Copy it into Claude, ChatGPT, or Copilot for a triage plan; the data is refreshed twice a day (5 AM and 3 PM US Central).
Fixed by the same update
If you are patching CVE-2026-40358, the same update also fixes these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.
