Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Win32K - GRFX allows an authorized attacker to elevate privileges locally.
The following code is for security research and authorized testing only.
python
#include <windows.h>
#include <stdio.h>
// Conceptual PoC for CVE-2026-33104
// This PoC demonstrates the threading mechanism required to trigger the race condition.
HANDLE hStartEvent;
DWORD WINAPI ExploitThread(LPVOID lpParam) {
// Wait for the main thread to signal the start
WaitForSingleObject(hStartEvent, INFINITE);
// Trigger the vulnerable Win32k GRFX function
// This involves specific API calls that race with the other thread
// Example: Triggering a callback while modifying a shared GDI object
return 0;
}
int main() {
hStartEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
HANDLE hThreads[2];
// Create multiple threads to race against each other
for (int i = 0; i < 2; i++) {
hThreads[i] = CreateThread(NULL, 0, ExploitThread, NULL, 0, NULL);
}
// Signal threads to start simultaneously
SetEvent(hStartEvent);
// Wait for execution
WaitForMultipleObjects(2, hThreads, TRUE, INFINITE);
printf("[+] Race condition triggered.");
return 0;
}