FKIE_CVE-2021-20196

Vulnerability from fkie_nvd - Published: 2021-05-26 22:15 - Updated: 2026-06-17 03:33
Severity
6.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Summary
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.
References
secalert@redhat.comhttps://bugs.launchpad.net/qemu/+bug/1912780Exploit, Patch, Third Party Advisory
secalert@redhat.comhttps://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
secalert@redhat.comhttps://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
secalert@redhat.comhttps://security.netapp.com/advisory/ntap-20210708-0004/Third Party Advisory
secalert@redhat.comhttps://www.openwall.com/lists/oss-security/2021/01/28/1Mailing List, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://bugs.launchpad.net/qemu/+bug/1912780Exploit, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20210708-0004/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2021/01/28/1Mailing List, Patch, Third Party Advisory
Impacted products
Vendor Product Version
qemu qemu 5.2.0
debian debian_linux 9.0
debian debian_linux 10.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "qemu",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "vulnerable up to (including) qemu 5.2.0"
            }
          ]
        }
      ],
      "source": "secalert@redhat.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:qemu:qemu:5.2.0:-:*:*:*:*:*:*",
              "matchCriteriaId": "9ABAD207-A430-497A-AB2C-DA7C1920FE17",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "DEECE5FC-CACF-4496-A3E7-164736409252",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "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 encontr\u00f3 un fallo de desreferencia de puntero NULL en el emulador floppy disk de QEMU.\u0026#xa0;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.\u0026#xa0;Este fallo permite a un usuario invitado privilegiado bloquear el proceso QEMU en el host, resultando en una denegaci\u00f3n de servicio.\u0026#xa0;La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema"
    }
  ],
  "id": "CVE-2021-20196",
  "lastModified": "2026-06-17T03:33:27.217",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "LOW",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 2.1,
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "vectorString": "AV:L/AC:L/Au:N/C:N/I:N/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 4.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-05-26T22:15:07.907",
  "references": [
    {
      "source": "secalert@redhat.com",
      "tags": [
        "Exploit",
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://bugs.launchpad.net/qemu/+bug/1912780"
    },
    {
      "source": "secalert@redhat.com",
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    },
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    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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      "url": "https://security.netapp.com/advisory/ntap-20210708-0004/"
    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://www.openwall.com/lists/oss-security/2021/01/28/1"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://bugs.launchpad.net/qemu/+bug/1912780"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      ],
      "url": "https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      "url": "https://security.netapp.com/advisory/ntap-20210708-0004/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      ],
      "url": "https://www.openwall.com/lists/oss-security/2021/01/28/1"
    }
  ],
  "sourceIdentifier": "secalert@redhat.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "secalert@redhat.com",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Secondary"
    }
  ]
}



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