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CVE-2020-29479

Estado: ModificadaAlta (8.8)—

Se detectó un problema en Xen versiones hasta 4.14.x. En la implementación de Ocaml xenstored, la representación interna del árbol tiene casos especiales para el nodo root, porque este nodo no tiene padre. Desafortunadamente, no fueron comprobados los permisos para determinadas operaciones en el nodo root. Los invitados no privilegiados pueden obtener y modificar permisos, enumerar y eliminar el nodo root. (Eliminar todo el árbol de xenstore es una denegación de servicio en todo el host).

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Lograr el acceso de escritura a xenstore también es posible. Todos los sistemas que usan oxenstored son vulnerables. La construcción y el uso de oxenstored es el valor predeterminado en la distribución Xen previa, si el compilador Ocaml está disponible. Los sistemas que utilizan C xenstored no son vulnerables

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 (3)

Debian — Debian LinuxFedoraproject — FedoraXEN — XEN

CWE

Referencias

JSON original (NVD)

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  "id": "CVE-2020-29479",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
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          "version": "2.0",
          "baseScore": 7.2,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C",
          "authentication": "NONE",
          "integrityImpact": "COMPLETE",
          "accessComplexity": "LOW",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "COMPLETE"
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        "acInsufInfo": false,
        "impactScore": 10,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.9,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
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          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
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        "impactScore": 6,
        "exploitabilityScore": 2
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  "affected": [
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      "affectedData": [
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          "vendor": "n/a",
          "product": "n/a",
          "versions": [
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              "status": "affected",
              "version": "n/a"
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  "published": "2020-12-15T18:15:14.897",
  "references": [
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      "url": "https://www.debian.org/security/2020/dsa-4812",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
        }
      ]
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation, the internal representation of the tree has special cases for the root node, because this node has no parent. Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable."
    },
    {
      "lang": "es",
      "value": "Se detectó un problema en Xen versiones hasta 4.14.x. En la implementación de Ocaml xenstored, la representación interna del árbol tiene casos especiales para el nodo root, porque este nodo no tiene padre. Desafortunadamente, no fueron comprobados los permisos para determinadas operaciones en el nodo root. Los invitados no privilegiados pueden obtener y modificar permisos, enumerar y eliminar el nodo root. (Eliminar todo el árbol de xenstore es una denegación de servicio en todo el host). Lograr el acceso de escritura a xenstore también es posible. Todos los sistemas que usan oxenstored son vulnerables. La construcción y el uso de oxenstored es el valor predeterminado en la distribución Xen previa, si el compilador Ocaml está disponible. Los sistemas que utilizan C xenstored no son vulnerables"
    }
  ],
  "lastModified": "2026-06-17T03:11:19.690",
  "configurations": [
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}