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CVE-2020-17469

Estado: ModificadaAlta (7.5)—

An issue was discovered in FNET through 4.6.4. The code for IPv6 fragment reassembly tries to access a previous fragment starting from a network incoming fragment that still doesn't have a reference to the previous one (which supposedly resides in the reassembly list). When faced with an incoming fragment that belongs to a non-empty fragment list, IPv6 reassembly must check that there are no empty holes between the fragments: this leads to an uninitialized pointer dereference in _fnet_ip6_reassembly in fnet_ip6.c, and causes Denial-of-Service.

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)

Butok — Fnet

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2020-17469",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-12-11T23:15:13.683",
  "references": [
    {
      "url": "http://fnet.sourceforge.net/manual/fnet_history.html",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://www.kb.cert.org/vuls/id/815128",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://fnet.sourceforge.net/manual/fnet_history.html",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.kb.cert.org/vuls/id/815128",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-824"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in FNET through 4.6.4. The code for IPv6 fragment reassembly tries to access a previous fragment starting from a network incoming fragment that still doesn't have a reference to the previous one (which supposedly resides in the reassembly list). When faced with an incoming fragment that belongs to a non-empty fragment list, IPv6 reassembly must check that there are no empty holes between the fragments: this leads to an uninitialized pointer dereference in _fnet_ip6_reassembly in fnet_ip6.c, and causes Denial-of-Service."
    },
    {
      "lang": "es",
      "value": "Se detectó un problema en FNET versiones hasta 4.6.4. El código para el reensamblaje de fragmentos IPv6 intenta acceder a un fragmento anterior a partir de un fragmento entrante de red que aún no cuenta con una referencia al anterior (que supuestamente reside en la lista de reensamblado). Cuando se enfrenta a un fragmento entrante que pertenece a una lista de fragmentos no vacíos, el reensamblaje de IPv6 debe comprobar que no haya huecos vacíos entre los fragmentos: esto conlleva a una desreferencia del puntero no inicializado en la función _fnet_ip6_reassembly en el archivo fnet_ip6.c, y causa una Denegación de Servicio"
    }
  ],
  "lastModified": "2026-06-17T02:58:58.950",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:butok:fnet:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F8E2831C-6C9A-4130-8993-2E5DF9F8F6F3",
              "versionEndIncluding": "4.6.4"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}