Patch tracker / CVE reference / CVE-2026-40403
CVE-2026-40403
CVE-2026-40403 is a critical severity Microsoft vulnerability with a CVSS score of 9.8. Its EPSS score puts the probability of exploitation in the next 30 days at 80%. Microsoft has shipped the fix: deploy one of the 16 updates 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 80%. CVSS 9.8 (Critical).
This CVE is among the top 25% of tracked Microsoft CVEs by EPSS exploit probability.
This is a Critical (CVSS 9.8) remote code execution flaw in the Windows Graphics Component affecting Windows 10 Version 1809 and Windows Server 2019, both older builds that often persist in server rooms and unmanaged endpoints. It is not on the CISA KEV list and has no known ransomware use, but the 80 percent EPSS score signals that exploitation is very likely to appear soon. Graphics component bugs are frequently reachable through document or image rendering, which widens the attack surface beyond direct network exposure.
Do this: Deploy Microsoft's patch for CVE-2026-40403 to all Windows 10 1809 and Windows Server 2019 systems this cycle, prioritizing internet-facing and multi-user hosts.
AI-generated from public data, 2026-07-26. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-40403
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Official patch(es) for CVE-2026-40403
High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5087420, KB5087423, KB5087424, KB5087470, KB5087471, KB5087537, KB5087538, KB5087539, KB5087541, KB5087544, KB5087545, KB5089466, KB5089548, KB5089549, KB5093998, KB5094127 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security updates below to fix CVE-2026-40403. 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 updates
- Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.