CVE-2026-45445 (GCVE-0-2026-45445)

Vulnerability from cvelistv5 – Published: 2026-06-09 16:03 – Updated: 2026-06-10 07:48
VLAI
Title
AES-OCB IV Ignored on EVP_Cipher() Path
Summary
Issue summary: When an application drives an AES-OCB context through the public EVP_Cipher() one-shot interface, the application-supplied initialisation vector (IV) is silently discarded. Impact summary: Every message encrypted under the same key uses the same effective nonce regardless of the IV supplied by the caller, resulting in (key, nonce) reuse and loss of confidentiality. If the same code path is used to compute the authentication tag, the tag depends only on the (key, IV) pair and not on the plaintext or ciphertext, allowing universal forgery of arbitrary ciphertext from a single captured message. OpenSSL provides two ways to drive a cipher: the documented streaming interface (EVP_CipherUpdate / EVP_CipherFinal_ex) and a lower-level one-shot, EVP_Cipher(), whose documentation explicitly recommends against use by applications in favour of EVP_CipherUpdate() and EVP_CipherFinal_ex(). The OCB provider's streaming handler flushes the application-supplied IV into the OCB context before processing data; the one-shot handler did not. Every call to EVP_Cipher() on an AES-OCB context therefore ran with the all-zero key-derived offset state left by cipher initialisation, regardless of the caller's IV. If EVP_EncryptFinal_ex() is subsequently used to obtain the authentication tag, the deferred IV setup runs at that point and clears the running checksum that should have been accumulated over the plaintext. The resulting tag is a function of (key, IV) only and verifies against any ciphertext produced under the same (key, IV) pair. The OpenSSL SSL/TLS implementation is not affected: AES-OCB is not a TLS cipher suite, and libssl does not call EVP_Cipher() in any case. Applications that drive AES-OCB through the documented streaming AEAD API (EVP_CipherUpdate / EVP_CipherFinal_ex) are not affected. Only applications that combine the AES-OCB cipher with the EVP_Cipher() one-shot API are vulnerable. The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as AES-OCB is outside the OpenSSL FIPS module boundary.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-09 19:22 UTC
CWE
  • CWE-325 - Missing Cryptographic Step
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
Alex Gaynor (Anthropic) Viktor Dukhovni
Show details on NVD website
To clipboard 

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            "value": "Issue summary: When an application drives an AES-OCB context through the\npublic EVP_Cipher() one-shot interface, the application-supplied\ninitialisation vector (IV) is silently discarded.\n\nImpact summary: Every message encrypted under the same key uses the\nsame effective nonce regardless of the IV supplied by the caller,\nresulting in (key, nonce) reuse and loss of confidentiality.  If the\nsame code path is used to compute the authentication tag, the tag\ndepends only on the (key, IV) pair and not on the plaintext or\nciphertext, allowing universal forgery of arbitrary ciphertext from a\nsingle captured message.\n\nOpenSSL provides two ways to drive a cipher: the documented streaming\ninterface (EVP_CipherUpdate / EVP_CipherFinal_ex) and a lower-level\none-shot, EVP_Cipher(), whose documentation explicitly recommends\nagainst use by applications in favour of EVP_CipherUpdate() and\nEVP_CipherFinal_ex().  The OCB provider\u0027s streaming handler flushes\nthe application-supplied IV into the OCB context before processing\ndata; the one-shot handler did not.  Every call to EVP_Cipher() on an\nAES-OCB context therefore ran with the all-zero key-derived offset\nstate left by cipher initialisation, regardless of the caller\u0027s IV.\n\nIf EVP_EncryptFinal_ex() is subsequently used to obtain the\nauthentication tag, the deferred IV setup runs at that point and\nclears the running checksum that should have been accumulated over the\nplaintext.  The resulting tag is a function of (key, IV) only and\nverifies against any ciphertext produced under the same (key, IV)\npair.\n\nThe OpenSSL SSL/TLS implementation is not affected: AES-OCB is not a\nTLS cipher suite, and libssl does not call EVP_Cipher() in any case.\nApplications that drive AES-OCB through the documented streaming AEAD\nAPI (EVP_CipherUpdate / EVP_CipherFinal_ex) are not affected.  Only\napplications that combine the AES-OCB cipher with the EVP_Cipher()\none-shot API are vulnerable.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\nthis issue, as AES-OCB is outside the OpenSSL FIPS module boundary."
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            "value": "Resumen del problema: Cuando una aplicaci\u00f3n maneja un contexto AES-OCB a trav\u00e9s de la interfaz de un solo uso p\u00fablica EVP_Cipher(), el vector de inicializaci\u00f3n (IV) proporcionado por la aplicaci\u00f3n es descartado silenciosamente.\n\nResumen del impacto: Cada mensaje cifrado bajo la misma clave utiliza el mismo nonce efectivo independientemente del IV proporcionado por el llamador, lo que resulta en la reutilizaci\u00f3n de (clave, nonce) y la p\u00e9rdida de confidencialidad. Si la misma ruta de c\u00f3digo se utiliza para calcular la etiqueta de autenticaci\u00f3n, la etiqueta depende solo del par (clave, IV) y no del texto plano o del texto cifrado, lo que permite la falsificaci\u00f3n universal de texto cifrado arbitrario a partir de un \u00fanico mensaje capturado.\n\nOpenSSL proporciona dos formas de manejar un cifrado: la interfaz de streaming documentada (EVP_CipherUpdate / EVP_CipherFinal_ex) y una de un solo uso de nivel inferior, EVP_Cipher(), cuya documentaci\u00f3n recomienda expl\u00edcitamente no ser utilizada por las aplicaciones en favor de EVP_CipherUpdate() y EVP_CipherFinal_ex(). El gestor de streaming del proveedor OCB vac\u00eda el IV proporcionado por la aplicaci\u00f3n en el contexto OCB antes de procesar los datos; el gestor de un solo uso no lo hac\u00eda. Cada llamada a EVP_Cipher() en un contexto AES-OCB, por lo tanto, se ejecutaba con el estado de desplazamiento derivado de la clave todo-cero dejado por la inicializaci\u00f3n del cifrado, independientemente del IV del llamador.\n\nSi EVP_EncryptFinal_ex() se utiliza posteriormente para obtener la etiqueta de autenticaci\u00f3n, la configuraci\u00f3n diferida del IV se ejecuta en ese momento y borra la suma de verificaci\u00f3n en ejecuci\u00f3n que deber\u00eda haberse acumulado sobre el texto plano. La etiqueta resultante es una funci\u00f3n de (clave, IV) solamente y verifica cualquier texto cifrado producido bajo el mismo par (clave, IV).\n\nLa implementaci\u00f3n SSL/TLS de OpenSSL no se ve afectada: AES-OCB no es una suite de cifrado TLS, y libssl no llama a EVP_Cipher() en ning\u00fan caso. Las aplicaciones que manejan AES-OCB a trav\u00e9s de la API AEAD de streaming documentada (EVP_CipherUpdate / EVP_CipherFinal_ex) no se ven afectadas. Solo las aplicaciones que combinan el cifrado AES-OCB con la API de un solo uso EVP_Cipher() son vulnerables.\n\nLos m\u00f3dulos FIPS en 4.0, 3.6, 3.5, 3.4 y 3.0 no se ven afectados por este problema, ya que AES-OCB est\u00e1 fuera del l\u00edmite del m\u00f3dulo FIPS de OpenSSL."
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        "id": "CVE-2026-45445",
        "lastModified": "2026-07-23T08:10:00.137",
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            "tags": [
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            ],
            "url": "https://github.com/openssl/openssl/commit/843c9b94ca9c2ed248bb30127bb4f3d7af0d607c"
          },
          {
            "source": "openssl-security@openssl.org",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/openssl/openssl/commit/983d54b5cce8d16147548ed1a37892d1720bbab6"
          },
          {
            "source": "openssl-security@openssl.org",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://openssl-library.org/news/secadv/20260609.txt"
          }
        ],
        "sourceIdentifier": "openssl-security@openssl.org",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-325"
              }
            ],
            "source": "openssl-security@openssl.org",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-19T10:29:44+00:00",
      "cve": "CVE-2026-45445",
      "id": "CVE-2026-45445",
      "initial_release_date": "2026-06-09T00:00:00+00:00",
      "product_status:fixed": "353",
      "product_status:known_affected": "2",
      "product_status:known_not_affected": "222",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "openssl: AES-OCB IV Ignored on EVP_Cipher() Path",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45445.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "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"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-45445",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-09T19:22:47.789275Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-09T19:22:42.527Z",
              "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": "Alex Gaynor (Anthropic)"
            },
            {
              "lang": "en",
              "type": "remediation developer",
              "value": "Viktor Dukhovni"
            }
          ],
          "datePublic": "2026-06-09T14:00:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "Issue summary: When an application drives an AES-OCB context through the\u003cbr\u003epublic EVP_Cipher() one-shot interface, the application-supplied\u003cbr\u003einitialisation vector (IV) is silently discarded.\u003cbr\u003e\u003cbr\u003eImpact summary: Every message encrypted under the same key uses the\u003cbr\u003esame effective nonce regardless of the IV supplied by the caller,\u003cbr\u003eresulting in (key, nonce) reuse and loss of confidentiality.  If the\u003cbr\u003esame code path is used to compute the authentication tag, the tag\u003cbr\u003edepends only on the (key, IV) pair and not on the plaintext or\u003cbr\u003eciphertext, allowing universal forgery of arbitrary ciphertext from a\u003cbr\u003esingle captured message.\u003cbr\u003e\u003cbr\u003eOpenSSL provides two ways to drive a cipher: the documented streaming\u003cbr\u003einterface (EVP_CipherUpdate / EVP_CipherFinal_ex) and a lower-level\u003cbr\u003eone-shot, EVP_Cipher(), whose documentation explicitly recommends\u003cbr\u003eagainst use by applications in favour of EVP_CipherUpdate() and\u003cbr\u003eEVP_CipherFinal_ex().  The OCB provider\u0027s streaming handler flushes\u003cbr\u003ethe application-supplied IV into the OCB context before processing\u003cbr\u003edata; the one-shot handler did not.  Every call to EVP_Cipher() on an\u003cbr\u003eAES-OCB context therefore ran with the all-zero key-derived offset\u003cbr\u003estate left by cipher initialisation, regardless of the caller\u0027s IV.\u003cbr\u003e\u003cbr\u003eIf EVP_EncryptFinal_ex() is subsequently used to obtain the\u003cbr\u003eauthentication tag, the deferred IV setup runs at that point and\u003cbr\u003eclears the running checksum that should have been accumulated over the\u003cbr\u003eplaintext.  The resulting tag is a function of (key, IV) only and\u003cbr\u003everifies against any ciphertext produced under the same (key, IV)\u003cbr\u003epair.\u003cbr\u003e\u003cbr\u003eThe OpenSSL SSL/TLS implementation is not affected: AES-OCB is not a\u003cbr\u003eTLS cipher suite, and libssl does not call EVP_Cipher() in any case.\u003cbr\u003eApplications that drive AES-OCB through the documented streaming AEAD\u003cbr\u003eAPI (EVP_CipherUpdate / EVP_CipherFinal_ex) are not affected.  Only\u003cbr\u003eapplications that combine the AES-OCB cipher with the EVP_Cipher()\u003cbr\u003eone-shot API are vulnerable.\u003cbr\u003e\u003cbr\u003eThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\u003cbr\u003ethis issue, as AES-OCB is outside the OpenSSL FIPS module boundary."
                }
              ],
              "value": "Issue summary: When an application drives an AES-OCB context through the\npublic EVP_Cipher() one-shot interface, the application-supplied\ninitialisation vector (IV) is silently discarded.\n\nImpact summary: Every message encrypted under the same key uses the\nsame effective nonce regardless of the IV supplied by the caller,\nresulting in (key, nonce) reuse and loss of confidentiality.  If the\nsame code path is used to compute the authentication tag, the tag\ndepends only on the (key, IV) pair and not on the plaintext or\nciphertext, allowing universal forgery of arbitrary ciphertext from a\nsingle captured message.\n\nOpenSSL provides two ways to drive a cipher: the documented streaming\ninterface (EVP_CipherUpdate / EVP_CipherFinal_ex) and a lower-level\none-shot, EVP_Cipher(), whose documentation explicitly recommends\nagainst use by applications in favour of EVP_CipherUpdate() and\nEVP_CipherFinal_ex().  The OCB provider\u0027s streaming handler flushes\nthe application-supplied IV into the OCB context before processing\ndata; the one-shot handler did not.  Every call to EVP_Cipher() on an\nAES-OCB context therefore ran with the all-zero key-derived offset\nstate left by cipher initialisation, regardless of the caller\u0027s IV.\n\nIf EVP_EncryptFinal_ex() is subsequently used to obtain the\nauthentication tag, the deferred IV setup runs at that point and\nclears the running checksum that should have been accumulated over the\nplaintext.  The resulting tag is a function of (key, IV) only and\nverifies against any ciphertext produced under the same (key, IV)\npair.\n\nThe OpenSSL SSL/TLS implementation is not affected: AES-OCB is not a\nTLS cipher suite, and libssl does not call EVP_Cipher() in any case.\nApplications that drive AES-OCB through the documented streaming AEAD\nAPI (EVP_CipherUpdate / EVP_CipherFinal_ex) are not affected.  Only\napplications that combine the AES-OCB cipher with the EVP_Cipher()\none-shot API are vulnerable.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\nthis issue, as AES-OCB is outside the OpenSSL FIPS module boundary."
            }
          ],
          "metrics": [
            {
              "format": "other",
              "other": {
                "content": {
                  "text": "Moderate"
                },
                "type": "https://openssl-library.org/policies/general/security-policy/"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-325",
                  "description": "CWE-325 Missing Cryptographic Step",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-06-10T07:48:10.949Z",
            "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/843c9b94ca9c2ed248bb30127bb4f3d7af0d607c"
            },
            {
              "name": "3.6.3 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/787a6dfba81b7b09c1e05ab31396c0cd7c36b3f7"
            },
            {
              "name": "3.5.7 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/983d54b5cce8d16147548ed1a37892d1720bbab6"
            },
            {
              "name": "3.4.6 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/7ac4715234ee72d9f3c93426a2c08554b5b771af"
            },
            {
              "name": "3.0.21 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/323f0b6e7d530a4cb4336d50c88cb70f3ac2a451"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "AES-OCB IV Ignored on EVP_Cipher() Path",
          "x_generator": {
            "engine": "Vulnogram 0.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
        "assignerShortName": "openssl",
        "cveId": "CVE-2026-45445",
        "datePublished": "2026-06-09T16:03:31.338Z",
        "dateReserved": "2026-05-12T14:34:06.276Z",
        "dateUpdated": "2026-06-10T07:48:10.949Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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