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CVE-2021-32802

Estado: ModificadaCrítica (9.8)—

Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. For some image types, the Nextcloud server was invoking a third-party library that wasn't suited for untrusted user-supplied content. There are several security concerns with passing user-generated content to this library, such as Server-Side-Request-Forgery, file disclosure or potentially executing code on the system. The risk depends on your system configuration and the installed library version. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. These versions do not use this library anymore. As a workaround users may disable previews by setting `enable_previews` to `false` in `config.php`.

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).

Tecnologías afectadas (1)

Nextcloud — Nextcloud Server

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2021-32802",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 10,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
          "authentication": "NONE",
          "integrityImpact": "COMPLETE",
          "accessComplexity": "LOW",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "COMPLETE"
        },
        "acInsufInfo": false,
        "impactScore": 10,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9.3,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 4.7,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "nextcloud",
          "product": "security-advisories",
          "versions": [
            {
              "status": "affected",
              "version": "< 20.0.12"
            },
            {
              "status": "affected",
              "version": ">= 21.0.0, < 21.0.4"
            },
            {
              "status": "affected",
              "version": ">= 22.0.0, < 22.1.0"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-09-07T22:15:08.563",
  "references": [
    {
      "url": "https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previews",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://hackerone.com/reports/1261413",
      "tags": [
        "Permissions Required",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://security.gentoo.org/glsa/202208-17",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://docs.nextcloud.com/server/21/admin_manual/configuration_files/previews_configuration.html#disabling-previews",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m682-v4g9-wrq7",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://hackerone.com/reports/1261413",
      "tags": [
        "Permissions Required",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://security.gentoo.org/glsa/202208-17",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-829"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-829"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. For some image types, the Nextcloud server was invoking a third-party library that wasn't suited for untrusted user-supplied content. There are several security concerns with passing user-generated content to this library, such as Server-Side-Request-Forgery, file disclosure or potentially executing code on the system. The risk depends on your system configuration and the installed library version. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. These versions do not use this library anymore. As a workaround users may disable previews by setting `enable_previews` to `false` in `config.php`."
    },
    {
      "lang": "es",
      "value": "El servidor Nextcloud es una nube personal de código abierto y autoalojada. Nextcloud admite la representación de vistas previas de imágenes para el contenido de archivos proporcionados por el usuario. Para algunos tipos de imágenes, el servidor Nextcloud estaba invocando una biblioteca de terceros que no era adecuada para el contenido no confiable proporcionado por el usuario. Se presentan varios problemas de seguridad al pasar contenido generado por el usuario a esta biblioteca, como un ataque de tipo Server-Side-Request-Forgery, una divulgación de archivos o una posible ejecución de código en el sistema. El riesgo depende de la configuración del sistema y de la versión de la biblioteca instalada. Es recomendado actualizar el servidor Nextcloud a versión 20.0.12, 21.0.4 o 22.1.0. Estas versiones ya no usan esta biblioteca. Como solución alternativa, los usuarios pueden deshabilitar las vistas previas al ajustar \"enable_previews\" a \"false\" en \"config.php\""
    }
  ],
  "lastModified": "2026-06-17T03:53:39.467",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "68C08D05-1FEC-4A5B-8925-B8D910541CEE",
              "versionEndExcluding": "20.0.12"
            },
            {
              "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B1D99183-A99E-4C56-991A-D4287EEDFE79",
              "versionEndExcluding": "21.0.4",
              "versionStartIncluding": "21.0.0"
            },
            {
              "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "655A23FE-6908-4F26-878C-29F9F2D269A6",
              "versionEndExcluding": "22.1.0",
              "versionStartIncluding": "22.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security-advisories@github.com"
}