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FKIE_CVE-2020-25683

Vulnerability from fkie_nvd - Published: 2021-01-20 16:15 - Updated: 2026-06-17 03:07
Severity
5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
References
secalert@redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=1882018Issue Tracking, Patch, Third Party Advisory
secalert@redhat.comhttps://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing List, Third Party Advisory
secalert@redhat.comhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
secalert@redhat.comhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
secalert@redhat.comhttps://security.gentoo.org/glsa/202101-17Third Party Advisory
secalert@redhat.comhttps://www.debian.org/security/2021/dsa-4844Third Party Advisory
secalert@redhat.comhttps://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1882018Issue Tracking, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202101-17Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.debian.org/security/2021/dsa-4844Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.kb.cert.org/vuls/id/434904
Impacted products
Vendor Product Version
thekelleys dnsmasq *
fedoraproject fedora 32
fedoraproject fedora 33
debian debian_linux 9.0
debian debian_linux 10.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "dnsmasq",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "dnsmasq 2.83"
            }
          ]
        }
      ],
      "source": "secalert@redhat.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "F38115DF-0F5C-442D-83D4-1125AAB4E2B7",
              "versionEndExcluding": "2.83",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
              "matchCriteriaId": "36D96259-24BD-44E2-96D9-78CE1D41F956",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
              "matchCriteriaId": "E460AA51-FCDA-46B9-AE97-E6676AA5E194",
              "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 flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability."
    },
    {
      "lang": "es",
      "value": "Se encontr\u00f3 un fallo en dnsmasq versiones anteriores a 2.83.\u0026#xa0;Se detect\u00f3 un desbordamiento del b\u00fafer en la regi\u00f3n heap de la memoria en dnsmasq cuando DNSSEC est\u00e1 habilitado y antes de comprobar las entradas DNS recibidas.\u0026#xa0;Un atacante remoto, que puede crear respuestas DNS v\u00e1lidas, podr\u00eda usar este fallo para causar un desbordamiento en una memoria asignada de la pila.\u0026#xa0;Este fallo es causado por una falta de comprobaci\u00f3n de longitud en rfc1035.c:extract_name(), que podr\u00eda ser abusado para causar que el c\u00f3digo ejecute memcpy() con un tama\u00f1o negativo en get_rdata() y causar un bloqueo en dnsmasq, lo que resultar\u00eda en una denegaci\u00f3n de servicio.\u0026#xa0;La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema"
    }
  ],
  "id": "CVE-2020-25683",
  "lastModified": "2026-06-17T03:07:07.293",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "HIGH",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "COMPLETE",
          "baseScore": 7.1,
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "vectorString": "AV:N/AC:M/Au:N/C:N/I:N/A:C",
          "version": "2.0"
        },
        "exploitabilityScore": 8.6,
        "impactScore": 6.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-01-20T16:15:14.087",
  "references": [
    {
      "source": "secalert@redhat.com",
      "tags": [
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1882018"
    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/"
    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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      ],
      "url": "https://security.gentoo.org/glsa/202101-17"
    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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      ],
      "url": "https://www.debian.org/security/2021/dsa-4844"
    },
    {
      "source": "secalert@redhat.com",
      "tags": [
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      ],
      "url": "https://www.jsof-tech.com/disclosures/dnspooq/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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    },
    {
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      "tags": [
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        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      "url": "https://security.gentoo.org/glsa/202101-17"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      "url": "https://www.debian.org/security/2021/dsa-4844"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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      "url": "https://www.jsof-tech.com/disclosures/dnspooq/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://www.kb.cert.org/vuls/id/434904"
    }
  ],
  "sourceIdentifier": "secalert@redhat.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "secalert@redhat.com",
      "type": "Secondary"
    }
  ]
}



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