Heap-based buffer overflow in Windows Win32K - GRFX allows an authorized attacker to execute code locally.
CVSS Details
CVSS Score
8.8
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Configurations (Affected Products)
No configuration data available.
Windows (具体受影响版本请参考微软安全公告)
PoC / Exploit Code
⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
/*
* PoC for CVE-2026-40403 (Conceptual)
* Triggering Heap Overflow in Win32k GRFX
*/
#include <windows.h>
#include <stdio.h>
void main() {
printf("[*] Starting PoC for CVE-2026-40403\n");
// 1. Allocate a large buffer to trigger overflow
SIZE_T size = 0x2000;
PVOID payload = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, size);
memset(payload, 0x41, size); // Fill with 'A'
// 2. Obtain Device Context (DC) to interact with Win32k
HDC hdc = GetDC(NULL);
// 3. Hypothetical trigger function
// In a real exploit, specific undocumented Win32k syscalls or
// GDI object manipulations would be used to pass the payload
// to the vulnerable kernel buffer.
// Example: VulnerableGdiCall(hdc, payload, size);
printf("[*] Payload prepared. Attempting to trigger vulnerability...\n");
// Trigger logic goes here
ReleaseDC(NULL, hdc);
HeapFree(GetProcessHeap(), 0, payload);
printf("[*] PoC execution finished.\n");
}