CVE-2026-34182 (GCVE-0-2026-34182)

Vulnerability from cvelistv5 – Published: 2026-06-09 16:03 – Updated: 2026-06-10 15:58
VLAI
Title
CMS AuthEnvelopedData Processing May Accept Forged Messages
Summary
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. 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.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-10 15:58 UTC
CWE
  • CWE-354 - Improper Validation of Integrity Check Value
Assigner
openssl CNA under the mitre root
CNA scorecard B 78/100 over 43 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
OpenSSL OpenSSL Affected: 4.0.0 , < 4.0.1 (semver)
Affected: 3.6.0 , < 3.6.3 (semver)
Affected: 3.5.0 , < 3.5.7 (semver)
Affected: 3.4.0 , < 3.4.6 (semver)
Affected: 3.0.0 , < 3.0.21 (semver)
guessed Create a notification for this product.
Date Public
2026-06-09 14:00
Credits
Asim Viladi Oglu Manizada Alex Gaynor (Anthropic) Ying Dong Haiyang Huang Neil Horman
Show details on NVD website
To clipboard 

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            "value": "Resumen del problema: El procesamiento de los Servicios de Mensajes Criptogr\u00e1ficos (CMS) no realiza una validaci\u00f3n 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 validaci\u00f3n 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 err\u00f3neamente esta selecci\u00f3n e intenta descifrar y validar el mensaje.\n\nUn atacante en la ruta que captura un AuthEnvelopedData AES-GCM leg\u00edtimo dirigido a la v\u00edctima puede reemitirlo con el conjunto recipientInfos intacto byte a byte, de modo que la clave privada de la v\u00edctima a\u00fan desenvuelve la CEK genuina (la clave de cifrado de contenido), pero con el OID interno reescrito a AES-256-OFB (Modo de Retroalimentaci\u00f3n de Salida, un modo de flujo de clave no autenticado) y con un IV y texto cifrado elegidos por el atacante. La v\u00edctima inicializa AES-256-OFB bajo la CEK real, nunca consulta el campo MAC, y CMS_decrypt() devuelve \u00e9xito.\n\nSi la aplicaci\u00f3n bajo ataque responde al atacante con cualquier indicador que muestre el \u00e9xito o fracaso del esfuerzo de descifrado, es posible que el atacante use esto como un or\u00e1culo 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 elusi\u00f3n de integridad para aplicaciones que conf\u00edan en que CMS_decrypt() rechace el contenido modificado.\n\nLos m\u00f3dulos FIPS no se ven afectados por este problema."
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                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "NETWORK",
                  "availabilityImpact": "NONE",
                  "baseScore": 9.1,
                  "baseSeverity": "CRITICAL",
                  "confidentialityImpact": "HIGH",
                  "integrityImpact": "HIGH",
                  "privilegesRequired": "NONE",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-34182",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-10T15:58:17.905043Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-10T15:56:46.661Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "OpenSSL",
              "vendor": "OpenSSL",
              "versions": [
                {
                  "lessThan": "4.0.1",
                  "status": "affected",
                  "version": "4.0.0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "3.6.3",
                  "status": "affected",
                  "version": "3.6.0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "3.5.7",
                  "status": "affected",
                  "version": "3.5.0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "3.4.6",
                  "status": "affected",
                  "version": "3.4.0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "3.0.21",
                  "status": "affected",
                  "version": "3.0.0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "Asim Viladi Oglu Manizada"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Alex Gaynor (Anthropic)"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Ying Dong"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Haiyang Huang"
            },
            {
              "lang": "en",
              "type": "remediation developer",
              "value": "Neil Horman"
            }
          ],
          "datePublic": "2026-06-09T14:00:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "Issue Summary: Cryptographic Message Services (CMS) processing fails to perform\u003cbr\u003esufficient input validation on the cipher and tag length fields of\u003cbr\u003eAuthEnvelopedData containers, leading to various potential compromises.\u003cbr\u003e\u003cbr\u003eImpact Summary: Attackers making use of these vulnerabilities may achieve\u003cbr\u003ekey-equivalent functionality for a given CMS recipient and/or bypass integrity\u003cbr\u003evalidation for a given message.\u003cbr\u003e\u003cbr\u003eIn one use case, an attacker may send a CMS message containing\u003cbr\u003eAuthEnvelopedData with the cipher specified as a non-AEAD cipher.  OpenSSL\u003cbr\u003eerroneously allows this selection, and attempts to decrypt and validate the\u003cbr\u003emessage.\u003cbr\u003e\u003cbr\u003eAn on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData\u003cbr\u003eaddressed to the victim can re-emit it with the recipientInfos set left\u003cbr\u003ebyte-for-byte intact, so the victim\u0027s private key still unwraps the genuine CEK\u003cbr\u003e(the content-encryption key), but with the inner OID rewritten to AES-256-OFB\u003cbr\u003e(Output Feedback Mode, an unauthenticated keystream mode) and with an\u003cbr\u003eattacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the\u003cbr\u003ereal CEK, never consults the MAC field, and CMS_decrypt() returns success.\u003cbr\u003e\u003cbr\u003eIf the application under attack responds to the attacker with any indicator\u003cbr\u003eshowing success or failure of the decryption effort, it is possible for the\u003cbr\u003eattacker to use this as an oracle to obtain key equivalent functionality for the\u003cbr\u003eCEK used for the chosen recipient of the message.\u003cbr\u003e\u003cbr\u003eIn another use case, an attacker can reduce the tag length of the chosen AEAD\u003cbr\u003ecipher for a given AuthEnvelopedData container to be a single byte long,\u003cbr\u003eallowing an attacker to brute force CMS decryption, producing an integrity\u003cbr\u003ebypass for applications that trust CMS_decrypt() to reject modified content.\u003cbr\u003e\u003cbr\u003eThe FIPS modules are not affected by this issue."
                }
              ],
              "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\u0027s 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."
            }
          ],
          "metrics": [
            {
              "format": "other",
              "other": {
                "content": {
                  "text": "Moderate"
                },
                "type": "https://openssl-library.org/policies/general/security-policy/"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-354",
                  "description": "CWE-354 Improper Validation of Integrity Check Value",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-06-10T07:47:54.994Z",
            "orgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
            "shortName": "openssl"
          },
          "references": [
            {
              "name": "OpenSSL Advisory",
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://openssl-library.org/news/secadv/20260609.txt"
            },
            {
              "name": "4.0.1 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/9fd97f8cfdc2c0be214998de3b2b55c8edf6c7ac"
            },
            {
              "name": "3.6.3 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/439ed7d2c0962ce964482727264668bf277c333f"
            },
            {
              "name": "3.5.7 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/7947e6a81eb8776802f159fb6762cb7fcf7e34c7"
            },
            {
              "name": "3.4.6 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/d2ca86bcd43e4f17d899f347101766b6107676e0"
            },
            {
              "name": "3.0.21 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/03c1f4d45fb963aee7d5833390c507cd290182bc"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "CMS AuthEnvelopedData Processing May Accept Forged Messages",
          "x_generator": {
            "engine": "Vulnogram 0.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
        "assignerShortName": "openssl",
        "cveId": "CVE-2026-34182",
        "datePublished": "2026-06-09T16:03:22.848Z",
        "dateReserved": "2026-03-26T09:29:36.013Z",
        "dateUpdated": "2026-06-10T15:58:52.695Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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