CVE-2026-6688

{
  "id": "CVE-2026-6688",
  "sourceIdentifier": "44488dab-36db-4358-99f9-bc116477f914",
  "published": "2026-07-01T15:17:13.013",
  "lastModified": "2026-10-25T17:10:00.197",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total."
    },
    {
      "lang": "es",
      "value": "FatFs R0.16 y anteriores contiene un patrón de vulnerabilidad de llamador descendente asociado con el manejo de nombres de archivo largos de FatFs. Con LFN habilitado, fno.fname puede tener hasta 255 caracteres; muchos llamadores lo copian en búferes fijos cortos sin comprobaciones de límites, causando desbordamiento. Esto corresponde a CWE-120 (Copia de búfer sin verificar el tamaño de la entrada). Vector CVSS v3.1 estimado: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, Alta). Los vectores SSVC de CISA estimados son Explotación: PoC, Impacto técnico: Total."
    }
  ],
  "affected": [
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "affectedData": [
        {
          "vendor": "ChaN",
          "product": "FatFs",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "R0.16",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "44488dab-36db-4358-99f9-bc116477f914",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
          "baseScore": 7.6,
          "baseSeverity": "HIGH",
          "attackVector": "PHYSICAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 0.9,
        "impactScore": 6.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-01T15:06:55.618764Z",
          "id": "CVE-2026-6688",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-120"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:elm-chan:fatfs:*:*:*:*:*:*:*:*",
              "versionEndIncluding": "r0.16",
              "matchCriteriaId": "B99160BB-C4F5-4DA0-9FC9-0723E0633E00"
            }
          ]
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  ],
  "references": [
    {
      "url": "https://elm-chan.org/fsw/ff/",
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Product"
      ]
    },
    {
      "url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance",
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ]
    },
    {
      "url": "https://www.runzero.com/advisories/fatfs-long-fn-of-downstream-cve-2026-6688/",
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.runzero.com/blog/fatfs-bugs/",
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ]
    },
    {
      "url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ]
    }
  ]
}