{"id":"CVE-2026-6683","state":"PUBLISHED","title":"FatFs Divide-by-Zero in exFAT Sync","description":"FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). 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). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.","publishedAt":"2026-07-01T13:41:11.337Z","updatedAt":"2026-07-01T15:24:56.449Z","severity":{"score":4.6,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"runZero"},"assigner":"runZero","products":["ChaN FatFs"],"affected":[{"vendor":"ChaN","product":"FatFs","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"R0.16","versionType":"custom"}]}],"references":["https://www.runzero.com/blog/fatfs-bugs/","https://github.com/runZeroInc/vulns-2026-fatfs-chance","https://elm-chan.org/fsw/ff/","https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683"],"weaknesses":["CWE-369"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/6xxx/CVE-2026-6683.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6683","state":"PUBLISHED","datePublished":"2026-07-01T13:41:11.337Z","dateUpdated":"2026-07-01T15:24:56.449Z","assignerShortName":"runZero","assignerOrgId":"44488dab-36db-4358-99f9-bc116477f914","dateReserved":"2026-04-20T15:06:19.048Z"},"containers":{"cna":{"title":"FatFs Divide-by-Zero in exFAT Sync","descriptions":[{"lang":"en","value":"FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). 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). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial."}],"affected":[{"vendor":"ChaN","product":"FatFs","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"R0.16","versionType":"custom"}]}],"references":[{"url":"https://www.runzero.com/blog/fatfs-bugs/","tags":["third-party-advisory"]},{"url":"https://github.com/runZeroInc/vulns-2026-fatfs-chance","tags":["technical-description"]},{"url":"https://elm-chan.org/fsw/ff/","tags":["product"]},{"url":"https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"PHYSICAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseSeverity":"MEDIUM","baseScore":4.6,"vectorString":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-369","lang":"en","description":"CWE-369 Divide by zero","type":"CWE"}]}],"providerMetadata":{"shortName":"runZero","orgId":"44488dab-36db-4358-99f9-bc116477f914","dateUpdated":"2026-07-01T14:11:06.688Z"},"datePublic":"2026-07-01T13:00:00.000Z","credits":[{"lang":"en","value":"HD Moore of runZero, Inc.","type":"finder"},{"lang":"en","value":"Tod Beardsley of runZero, Inc.","type":"coordinator"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/runZeroInc/vulns-2026-fatfs-chance","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-01T15:24:38.147110Z","id":"CVE-2026-6683","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-01T15:24:56.449Z"}}]}}}