« Volver al listado

CVE-2026-34182

Estado: AnalizadaCrítica (9.1)—

Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises.

Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message.

In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message.

Leer descripción completaMostrar menos

An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with an attacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the real CEK, never consults the MAC field, and CMS_decrypt() returns success.

If the application under attack responds to the attacker with any indicator showing success or failure of the decryption effort, it is possible for the attacker to use this as an oracle to obtain key equivalent functionality for the CEK used for the chosen recipient of the message.

In another use case, an attacker can reduce the tag length of the chosen AEAD cipher for a given AuthEnvelopedData container to be a single byte long, allowing an attacker to brute force CMS decryption, producing an integrity bypass for applications that trust CMS_decrypt() to reject modified content.

The FIPS modules are not affected by this issue.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad remota sin privilegios ni interacción (AV:N/PR:N/UI:N) en procesamiento CMS de OpenSSL. El atacante obtiene equivalencia de clave o bypassa validación de integridad manipulando cifrados y etiquetas de autenticación.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkVulnerability ScanningUser Account ManagementRestrict File and Directory Permissions

Tecnologías afectadas (1)

Openssl — Openssl

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-34182",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-34182",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-10T15:58:17.905043Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.1,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "openssl-security@openssl.org",
      "affectedData": [
        {
          "vendor": "OpenSSL",
          "product": "OpenSSL",
          "versions": [
            {
              "status": "affected",
              "version": "4.0.0",
              "lessThan": "4.0.1",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.6.0",
              "lessThan": "3.6.3",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.5.0",
              "lessThan": "3.5.7",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.4.0",
              "lessThan": "3.4.6",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.0.0",
              "lessThan": "3.0.21",
              "versionType": "semver"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-06-09T17:17:04.857",
  "references": [
    {
      "url": "https://github.com/openssl/openssl/commit/03c1f4d45fb963aee7d5833390c507cd290182bc",
      "tags": [
        "Patch"
      ],
      "source": "openssl-security@openssl.org"
    },
    {
      "url": "https://github.com/openssl/openssl/commit/439ed7d2c0962ce964482727264668bf277c333f",
      "tags": [
        "Patch"
      ],
      "source": "openssl-security@openssl.org"
    },
    {
      "url": "https://github.com/openssl/openssl/commit/7947e6a81eb8776802f159fb6762cb7fcf7e34c7",
      "tags": [
        "Patch"
      ],
      "source": "openssl-security@openssl.org"
    },
    {
      "url": "https://github.com/openssl/openssl/commit/9fd97f8cfdc2c0be214998de3b2b55c8edf6c7ac",
      "tags": [
        "Patch"
      ],
      "source": "openssl-security@openssl.org"
    },
    {
      "url": "https://github.com/openssl/openssl/commit/d2ca86bcd43e4f17d899f347101766b6107676e0",
      "tags": [
        "Patch"
      ],
      "source": "openssl-security@openssl.org"
    },
    {
      "url": "https://openssl-library.org/news/secadv/20260609.txt",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "openssl-security@openssl.org"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "openssl-security@openssl.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-354"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue Summary: Cryptographic Message Services (CMS) processing fails to perform\nsufficient input validation on the cipher and tag length fields of\nAuthEnvelopedData containers, leading to various potential compromises.\n\nImpact Summary: Attackers making use of these vulnerabilities may achieve\nkey-equivalent functionality for a given CMS recipient and/or bypass integrity\nvalidation for a given message.\n\nIn one use case, an attacker may send a CMS message containing\nAuthEnvelopedData with the cipher specified as a non-AEAD cipher.  OpenSSL\nerroneously allows this selection, and attempts to decrypt and validate the\nmessage.\n\nAn on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData\naddressed to the victim can re-emit it with the recipientInfos set left\nbyte-for-byte intact, so the victim's private key still unwraps the genuine CEK\n(the content-encryption key), but with the inner OID rewritten to AES-256-OFB\n(Output Feedback Mode, an unauthenticated keystream mode) and with an\nattacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the\nreal CEK, never consults the MAC field, and CMS_decrypt() returns success.\n\nIf the application under attack responds to the attacker with any indicator\nshowing success or failure of the decryption effort, it is possible for the\nattacker to use this as an oracle to obtain key equivalent functionality for the\nCEK used for the chosen recipient of the message.\n\nIn another use case, an attacker can reduce the tag length of the chosen AEAD\ncipher for a given AuthEnvelopedData container to be a single byte long,\nallowing an attacker to brute force CMS decryption, producing an integrity\nbypass for applications that trust CMS_decrypt() to reject modified content.\n\nThe FIPS modules are not affected by this issue."
    },
    {
      "lang": "es",
      "value": "Resumen del problema: El procesamiento de los Servicios de Mensajes Criptográficos (CMS) no realiza una validación de entrada suficiente en los campos de cifrado y longitud de etiqueta de los contenedores AuthEnvelopedData, lo que lleva a varias posibles compromisos.\n\nResumen del impacto: Los atacantes que aprovechan estas vulnerabilidades pueden lograr una funcionalidad equivalente a la clave para un destinatario CMS dado y/o eludir la validación de integridad para un mensaje dado.\n\nEn un caso de uso, un atacante puede enviar un mensaje CMS que contiene AuthEnvelopedData con el cifrado especificado como un cifrado no AEAD. OpenSSL permite erróneamente esta selección e intenta descifrar y validar el mensaje.\n\nUn atacante en la ruta que captura un AuthEnvelopedData AES-GCM legítimo dirigido a la víctima puede reemitirlo con el conjunto recipientInfos intacto byte a byte, de modo que la clave privada de la víctima aún desenvuelve la CEK genuina (la clave de cifrado de contenido), pero con el OID interno reescrito a AES-256-OFB (Modo de Retroalimentación de Salida, un modo de flujo de clave no autenticado) y con un IV y texto cifrado elegidos por el atacante. La víctima inicializa AES-256-OFB bajo la CEK real, nunca consulta el campo MAC, y CMS_decrypt() devuelve éxito.\n\nSi la aplicación bajo ataque responde al atacante con cualquier indicador que muestre el éxito o fracaso del esfuerzo de descifrado, es posible que el atacante use esto como un oráculo para obtener una funcionalidad equivalente a la clave para la CEK utilizada para el destinatario elegido del mensaje.\n\nEn otro caso de uso, un atacante puede reducir la longitud de la etiqueta del cifrado AEAD elegido para un contenedor AuthEnvelopedData dado a una longitud de un solo byte, permitiendo a un atacante forzar por fuerza bruta el descifrado CMS, produciendo una elusión de integridad para aplicaciones que confían en que CMS_decrypt() rechace el contenido modificado.\n\nLos módulos FIPS no se ven afectados por este problema."
    }
  ],
  "lastModified": "2026-07-23T08:10:00.137",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EDB88756-EDFE-4886-A267-3F19342A6042",
              "versionEndExcluding": "3.0.21",
              "versionStartIncluding": "3.0.0"
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "BF7E21E7-AEC0-4882-B1F1-2D056B506F22",
              "versionEndExcluding": "3.4.6",
              "versionStartIncluding": "3.4.0"
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6B6B9930-C549-4D88-9784-AF32CCDDB87A",
              "versionEndExcluding": "3.5.7",
              "versionStartIncluding": "3.5.0"
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D41B3C45-EC73-4DC8-989D-B2E2792E102F",
              "versionEndExcluding": "3.6.3",
              "versionStartIncluding": "3.6.0"
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6E881B9A-1A0A-4BC0-8160-20C00561167D"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "openssl-security@openssl.org"
}