CVE-2026-6688

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "FatFs", "vendor": "ChaN", "versions": [{"lessThanOrEqual": "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": "B99160BB-C4F5-4DA0-9FC9-0723E0633E00", "versionEndIncluding": "r0.16", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "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 patr\u00f3n 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 b\u00faferes fijos cortos sin comprobaciones de l\u00edmites, causando desbordamiento. Esto corresponde a CWE-120 (Copia de b\u00fafer sin verificar el tama\u00f1o 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 Explotaci\u00f3n: PoC, Impacto t\u00e9cnico: Total."}], "id": "CVE-2026-6688", "lastModified": "2026-10-25T17:10:00.197", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "PHYSICAL", "availabilityImpact": "HIGH", "baseScore": 7.6, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 0.9, "impactScore": 6.0, "source": "44488dab-36db-4358-99f9-bc116477f914", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-6688", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-07-01T15:06:55.618764Z", "version": "2.0.3"}}]}, "published": "2026-07-01T15:17:13.013", "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-long-fn-of-downstream-cve-2026-6688/"}, {"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-120"}], "source": "44488dab-36db-4358-99f9-bc116477f914", "type": "Secondary"}]}

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