CVE-2026-40403

HIGH

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

CVSS v3.1 Score

8.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 5/12/2026Modified: 5/15/2026

Related Intelligence (1)

CRITICALAi

Patch Tuesday - May 2026

Microsoft is publishing 137 vulnerabilities on May 2026 Patch Tuesday . Microsoft is not aware of exploitation in the wild or public disclosure for any of these vulnerabilities. So far this month, Microsoft has provided patches to address 133 browser vulnerabilities, which are not included in the Patch Tuesday count above. Windows Netlogon: critical RCE Anyone responsible for securing a domain con

CVE-2026-41089CVE-2020-1472
Rapid7

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40403Vendor Advisory