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CVE-2026-54412

Full vulnerability record from the local CVENow database.

Description

LiamBindle MQTT-C versions prior to 1.1.7 contain a heap-based out-of-bounds read and integer underflow in the mqtt_unpack_publish_response() function in src/mqtt.c. A remote unauthenticated attacker controlling an MQTT broker, or capable of injecting MQTT traffic into an unencrypted session, can crash a subscribed MQTT-C client and potentially disclose adjacent heap memory by sending a single crafted PUBLISH packet.

Severity
HIGH
CVSS score
7.8 (v4.0)
Vulnerability status
Deferred
Source identifier
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
Published
2026-06-14 18:17:20.750000
Last modified
2026-11-05 13:17:07.963000
View original CVE JSON 
{
  "id": "CVE-2026-54412",
  "sourceIdentifier": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
  "published": "2026-06-14T18:17:20.750",
  "lastModified": "2026-11-05T13:17:07.963",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "LiamBindle MQTT-C versions prior to 1.1.7 contain a heap-based out-of-bounds read and integer underflow in the mqtt_unpack_publish_response() function in src/mqtt.c. A remote unauthenticated attacker controlling an MQTT broker, or capable of injecting MQTT traffic into an unencrypted session, can crash a subscribed MQTT-C client and potentially disclose adjacent heap memory by sending a single crafted PUBLISH packet."
    },
    {
      "lang": "es",
      "value": "LiamBindle MQTT-C hasta la versión 1.1.6 contiene una lectura fuera de límites basada en el heap y un desbordamiento negativo de enteros en la función mqtt_unpack_publish_response() en src/mqtt.c que permite a un atacante remoto no autenticado que controla un broker MQTT - o capaz de inyectar tráfico MQTT en una sesión no cifrada - provocar la caída de un cliente MQTT-C suscrito y potencialmente divulgar memoria adyacente del heap enviando un único paquete PUBLISH manipulado. La función solo valida que el remaining_length del encabezado fijo sea al menos 4, luego lee el campo topic_name_size de 16 bits del paquete controlado por el broker y avanza el puntero de análisis por ese valor sin verificar que topic_name_size más la sobrecarga circundante encaje dentro de remaining_length; posteriormente calcula application_message_size como remaining_length - topic_name_size - 2 (QoS 0) o - 4 (QoS mayor que 0) en aritmética sin signo, produciendo un desbordamiento negativo de enteros que luego se pasa a memmove(). Un paquete PUBLISH con topic_name_size = 0xFFFF y remaining_length = 7 avanza el puntero de análisis 65535 bytes más allá del búfer de recepción (lectura fuera de límites) y provoca un application_message_size cercano a 2^32, provocando la caída del proceso cuando se ejecuta el memmove() resultante."
    }
  ],
  "affected": [
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "affectedData": [
        {
          "vendor": "LiamBindle",
          "product": "MQTT-C",
          "defaultStatus": "unknown",
          "collectionURL": "https://github.com/LiamBindle/MQTT-C",
          "programFiles": [
            "src/mqtt.c"
          ],
          "programRoutines": [
            {
              "name": "mqtt_unpack_publish_response"
            }
          ],
          "repo": "https://github.com/LiamBindle/MQTT-C",
          "versions": [
            {
              "version": "0",
              "lessThan": "1.1.7",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "1.1.7",
              "versionType": "semver",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:D/RE:X/U:X",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "PROOF_OF_CONCEPT",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "YES",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "DIFFUSE",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-06-15T17:01:08.771614Z",
          "id": "CVE-2026-54412",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        },
        {
          "lang": "en",
          "value": "CWE-191"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cwe.mitre.org/data/definitions/125.html",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://cwe.mitre.org/data/definitions/191.html",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://github.com/LiamBindle/MQTT-C",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://github.com/LiamBindle/MQTT-C/blob/v1.1.6/src/mqtt.c#L1334",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://github.com/LiamBindle/MQTT-C/pull/208",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://github.com/LiamBindle/MQTT-C/releases/tag/v1.1.7",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    }
  ]
}