CVE-2021-32677

{
  "id": "CVE-2021-32677",
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          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
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        "acInsufInfo": false,
        "impactScore": 4.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
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        "obtainOtherPrivilege": false,
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          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
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        "impactScore": 5.2,
        "exploitabilityScore": 2.8
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  "affected": [
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      "affectedData": [
        {
          "vendor": "tiangolo",
          "product": "fastapi",
          "versions": [
            {
              "status": "affected",
              "version": "< 0.65.2"
            }
          ]
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  "published": "2021-06-09T18:15:08.553",
  "references": [
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      "url": "https://github.com/tiangolo/fastapi/commit/fa7e3c996edf2d5482fff8f9d890ac2390dede4d",
      "tags": [
        "Patch",
        "Third Party Advisory"
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      "url": "https://github.com/tiangolo/fastapi/security/advisories/GHSA-8h2j-cgx8-6xv7",
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        "Third Party Advisory"
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    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MATAWX25TYKNEKLDMKWNLYDB34UWTROA/",
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      "url": "https://github.com/tiangolo/fastapi/commit/fa7e3c996edf2d5482fff8f9d890ac2390dede4d",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-352"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints. FastAPI versions lower than 0.65.2 that used cookies for authentication in path operations that received JSON payloads sent by browsers were vulnerable to a Cross-Site Request Forgery (CSRF) attack. In versions lower than 0.65.2, FastAPI would try to read the request payload as JSON even if the content-type header sent was not set to application/json or a compatible JSON media type (e.g. application/geo+json). A request with a content type of text/plain containing JSON data would be accepted and the JSON data would be extracted. Requests with content type text/plain are exempt from CORS preflights, for being considered Simple requests. The browser will execute them right away including cookies, and the text content could be a JSON string that would be parsed and accepted by the FastAPI application. This is fixed in FastAPI 0.65.2. The request data is now parsed as JSON only if the content-type header is application/json or another JSON compatible media type like application/geo+json. It's best to upgrade to the latest FastAPI, but if updating is not possible then a middleware or a dependency that checks the content-type header and aborts the request if it is not application/json or another JSON compatible content type can act as a mitigating workaround."
    },
    {
      "lang": "es",
      "value": "FastAPI es un framework web para construir APIs con Python versión 3.6+ basado en sugerencias de tipo estándar de Python. Las versiones de FastAPI inferiores a la 0.65.2 que usaban cookies para la autenticación en las operaciones de ruta que recibían cargas útiles JSON enviadas por los navegadores eran vulnerables a un ataque de tipo Cross-Site Request Forgery (CSRF). En versiones inferiores a la 0.65.2, FastAPI intentaba leer la carga útil de la petición como JSON incluso si la encabezado content-type enviada no estaba configurada como application/json o un tipo de medio JSON compatible (por ejemplo, application/geo+json). Una petición con un tipo de contenido text/plain que contenga datos JSON será aceptada y los datos JSON serán extraídos. Las peticiones con tipo de contenido text/plain están exentas de preflights CORS, por ser consideradas peticiones simples. El navegador las ejecutará de inmediato, incluyendo las cookies, y el contenido de texto podría ser una cadena JSON que sería analizada y aceptada por la aplicación FastAPI. Esto se ha corregido en FastAPI 0.65.2. Ahora los datos de la petición se analizan como JSON sólo si la encabezado content-type es application/json u otro tipo de medio compatible con JSON como application/geo+json. Es mejor actualizar a la última FastAPI, pero si la actualización no es posible, entonces un middleware o una dependencia que compruebe la encabezado de tipo de contenido y aborte la petición si no es application/json u otro tipo de contenido compatible con JSON puede actuar como una solución de mitigación"
    }
  ],
  "lastModified": "2026-06-17T03:53:24.237",
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