FKIE_CVE-2026-6684

Vulnerability from fkie_nvd - Published: 2026-07-01 15:17 - Updated: 2026-07-02 14:38
Severity
4.6 (Medium) - CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
References
44488dab-36db-4358-99f9-bc116477f914https://elm-chan.org/fsw/ff/Product
44488dab-36db-4358-99f9-bc116477f914https://github.com/runZeroInc/vulns-2026-fatfs-chanceThird Party Advisory, Exploit
44488dab-36db-4358-99f9-bc116477f914https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/Third Party Advisory
44488dab-36db-4358-99f9-bc116477f914https://www.runzero.com/blog/fatfs-bugs/Third Party Advisory, Exploit
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/runZeroInc/vulns-2026-fatfs-chanceThird Party Advisory, Exploit
Impacted products
Vendor Product Version
elm-chan fatfs *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "FatFs",
          "vendor": "ChaN",
          "versions": [
            {
              "lessThan": "R0.16",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "44488dab-36db-4358-99f9-bc116477f914"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:elm-chan:fatfs:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "4140C7A2-22F3-4919-AF38-C8F13F12B9F7",
              "versionEndExcluding": "r0.16",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "FatFs prior to R0.16 that use GPT scanning with \u0027FF_LBA64 = 1\u0027 contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."
    }
  ],
  "id": "CVE-2026-6684",
  "lastModified": "2026-07-02T14:38:25.923",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "PHYSICAL",
          "availabilityImpact": "HIGH",
          "baseScore": 4.6,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 0.9,
        "impactScore": 3.6,
        "source": "44488dab-36db-4358-99f9-bc116477f914",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-6684",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-01T15:25:35.369745Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-01T15:17:12.553",
  "references": [
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Product"
      ],
      "url": "https://elm-chan.org/fsw/ff/"
    },
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ],
      "url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
    },
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/"
    },
    {
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ],
      "url": "https://www.runzero.com/blog/fatfs-bugs/"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Third Party Advisory",
        "Exploit"
      ],
      "url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
    }
  ],
  "sourceIdentifier": "44488dab-36db-4358-99f9-bc116477f914",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        }
      ],
      "source": "44488dab-36db-4358-99f9-bc116477f914",
      "type": "Secondary"
    }
  ]
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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