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CVE-2021-20196

Estado: ModificadaMedia (6.5)—

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

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 (2)

Debian — Debian LinuxQemu — Qemu

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2021-20196",
  "cveTags": [],
  "metrics": {
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        "source": "nvd@nist.gov",
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          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
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          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
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        "acInsufInfo": false,
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        "obtainAllPrivilege": false,
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          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
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  "affected": [
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      "affectedData": [
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          "vendor": "n/a",
          "product": "qemu",
          "versions": [
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              "version": "vulnerable up to (including) qemu 5.2.0"
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  "published": "2021-05-26T22:15:07.907",
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Secondary",
      "source": "secalert@redhat.com",
      "description": [
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          "value": "CWE-476"
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  "descriptions": [
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      "lang": "en",
      "value": "A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability."
    },
    {
      "lang": "es",
      "value": "Se encontró un fallo de desreferencia de puntero NULL en el emulador floppy disk de QEMU. Este problema ocurre mientras se procesan comandos de ioport de lectura y escritura si la unidad de disquete seleccionada no es inicializada con un dispositivo de bloque. Este fallo permite a un usuario invitado privilegiado bloquear el proceso QEMU en el host, resultando en una denegación de servicio. La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema"
    }
  ],
  "lastModified": "2026-06-17T03:33:27.217",
  "configurations": [
    {
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}