{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:trustedfirmware:mbed_tls:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "556B943C-53E7-4B72-BFD9-086BD2384F5D",
              "versionEndExcluding": "3.6.6",
              "versionStartIncluding": "3.1.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Mbed TLS 3.x before 3.6.6. An out-of-bounds read vulnerability in mbedtls_ccm_finish() in library/ccm.c allows attackers to obtain adjacent CCM context data via invocation of the multipart CCM API with an oversized tag_len parameter. This is caused by missing validation of the tag_len parameter against the size of the internal 16-byte authentication buffer. The issue affects the public multipart CCM API in Mbed TLS 3.x, where mbedtls_ccm_finish() can be invoked directly by applications. In Mbed TLS 4.x versions prior to the fix, the same missing validation exists in the internal implementation; however, the function is not exposed as part of the public API. Exploitation requires application-level invocation of the multipart CCM API."
    },
    {
      "lang": "es",
      "value": "Se descubri\u00f3 un problema en Mbed TLS 3.x anterior a 3.6.6. Una vulnerabilidad de lectura fuera de l\u00edmites en mbedtls_ccm_finish() en biblioteca/ccm.c permite a los atacantes obtener datos de contexto CCM adyacentes mediante la invocaci\u00f3n de la API CCM multiparte con un par\u00e1metro tag_len de tama\u00f1o excesivo. Esto es causado por la falta de validaci\u00f3n del par\u00e1metro tag_len contra el tama\u00f1o del b\u00fafer de autenticaci\u00f3n interno de 16 bytes. El problema afecta a la API CCM multiparte p\u00fablica en Mbed TLS 3.x, donde mbedtls_ccm_finish() puede ser invocado directamente por las aplicaciones. En las versiones de Mbed TLS 4.x anteriores a la correcci\u00f3n, la misma falta de validaci\u00f3n existe en la implementaci\u00f3n interna; sin embargo, la funci\u00f3n no est\u00e1 expuesta como parte de la API p\u00fablica. La explotaci\u00f3n requiere la invocaci\u00f3n a nivel de aplicaci\u00f3n de la API CCM multiparte."
    }
  ],
  "id": "CVE-2026-34876",
  "lastModified": "2026-07-24T21:10:00.143",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-34876",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-04-02T15:53:54.288854Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-04-02T16:16:26.180",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ccm-finish-boundary-check/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}