CVE-2025-56352

{
  "id": "CVE-2025-56352",
  "sourceIdentifier": "[email protected]",
  "published": "2026-05-18T16:16:29.130",
  "lastModified": "2026-11-04T20:10:00.263",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), the broker mishandles protocol violations during CONNECT packet parsing. When receiving a CONNECT packet with a zero-length Client ID while CleanSession is set to 0, the broker correctly replies with a CONNACK return code 0x02 (Identifier Rejected) but fails to explicitly close the TCP connection. Since the surrounding connection teardown logic is not guaranteed to execute, each such invalid CONNECT attempt leaves the underlying socket open. Repeated attempts cause server-side resource exhaustion due to accumulating file descriptors and memory usage, potentially resulting in denial of service."
    },
    {
      "lang": "es",
      "value": "En el commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18) de tinyMQTT, el broker maneja incorrectamente las violaciones del protocolo durante el análisis de paquetes CONNECT. Al recibir un paquete CONNECT con un ID de cliente de longitud cero mientras CleanSession está configurado en 0, el broker responde correctamente con un código de retorno CONNACK 0x02 (Identificador Rechazado) pero no cierra explícitamente la conexión TCP. Dado que la lógica de cierre de conexión circundante no está garantizada para ejecutarse, cada intento CONNECT inválido de este tipo deja el socket subyacente abierto. Los intentos repetidos causan el agotamiento de recursos del lado del servidor debido a la acumulación de descriptores de archivo y el uso de memoria, lo que puede resultar en una denegación de servicio."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "version": "n/a",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "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: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
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-05-18T17:22:27.393806Z",
          "id": "CVE-2025-56352",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/JustDoIt0910/tinyMQTT/issues/19",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/user-attachments/files/21207896/Resource_Exhaustion_Poc.txt",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}