Buffer overflow in Microsoft Windows_10_1607

CVE-2026-40403

Heap-based buffer overflow in Windows Win32K - GRFX allows an authorized attacker to execute code locally.

Vulnerability class: Buffer Overflow

EPSS: 0.000 (4.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-40403?
CVE-2026-40403 is a high-severity vulnerability in Microsoft Windows_10_1607, classified under Heap-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-05-12.
How severe is CVE-2026-40403?
High severity. CVSS v3 base score is 8.8 out of 10.