FKIE_CVE-2026-76816

Vulnerability from fkie_nvd - Published: 2026-08-24 20:17 - Updated: 2026-10-12 21:10
Severity
3.5 (Low) - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Summary
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty's MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
References
security-advisories@github.comhttps://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
security-advisories@github.comhttps://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961
security-advisories@github.comhttps://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "netty",
          "vendor": "netty",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.2.0.Final, \u003c 4.1.137.Final"
            },
            {
              "status": "affected",
              "version": "\u003c 4.1.137.Final"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty\u0027s MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final."
    },
    {
      "lang": "es",
      "value": "Netty es un framework de aplicaci\u00f3n de red as\u00edncrono y basado en eventos. Antes de las versiones 4.1.137.Final y 4.2.17.Final, MqttEncoder no valida los identificadores de cliente, los temas de voluntad, los nombres de usuario y los nombres de temas PUBLISH antes de la codificaci\u00f3n, lo que permite bytes nulos prohibidos en los campos de cadena UTF-8 de MQTT y potencialmente causa desajustes de enrutamiento, control de acceso o identidad en brokers posteriores. La vulnerabilidad es explotable cuyo una aplicaci\u00f3n utiliza el codificador MQTT de Netty para construir mensajes a partir de entradas controladas por el usuario. Este problema est\u00e1 solucionado en las versiones 4.1.137.Final y 4.2.17.Final."
    }
  ],
  "id": "CVE-2026-76816",
  "lastModified": "2026-10-12T21:10:00.227",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.5,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.1,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-76816",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-25T13:34:40.707005Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-24T20:17:19.477",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-626"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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