FKIE_CVE-2026-45445
Vulnerability from fkie_nvd - Published: 2026-06-09 17:17 - Updated: 2026-07-23 08:10
Severity
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.
References
{
"affected": [
{
"affectedData": [
{
"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"
}
]
}
],
"source": "openssl-security@openssl.org"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EDB88756-EDFE-4886-A267-3F19342A6042",
"versionEndExcluding": "3.0.21",
"versionStartIncluding": "3.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "BF7E21E7-AEC0-4882-B1F1-2D056B506F22",
"versionEndExcluding": "3.4.6",
"versionStartIncluding": "3.4.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6B6B9930-C549-4D88-9784-AF32CCDDB87A",
"versionEndExcluding": "3.5.7",
"versionStartIncluding": "3.5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "D41B3C45-EC73-4DC8-989D-B2E2792E102F",
"versionEndExcluding": "3.6.3",
"versionStartIncluding": "3.6.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*",
"matchCriteriaId": "6E881B9A-1A0A-4BC0-8160-20C00561167D",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"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."
},
{
"lang": "es",
"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."
}
],
"id": "CVE-2026-45445",
"lastModified": "2026-07-23T08:10:00.137",
"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-2026-45445",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-09T19:22:47.789275Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-06-09T17:17:18.993",
"references": [
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/323f0b6e7d530a4cb4336d50c88cb70f3ac2a451"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/787a6dfba81b7b09c1e05ab31396c0cd7c36b3f7"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/7ac4715234ee72d9f3c93426a2c08554b5b771af"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"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"
}
]
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
Loading…
Loading…