{"id":"CVE-2026-6687","aliases":["EUVD-2026-40999","GHSA-wghw-hg6m-7rh3"],"status":"published","title":"FatFs Stack Buffer Overflow via Uncapped exFAT Label Length","description":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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.","severity":{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00348,"percentile":0.28687,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-121"],"published":"2026-07-01T13:57:54Z","modified":"2026-10-25T17:10:00Z","products":[{"vendor":"chan","product":"fatfs"},{"vendor":"elm-chan","product":"fatfs"}],"references":[{"url":"https://www.runzero.com/blog/fatfs-bugs/","tags":["third-party-advisory","Third Party Advisory","Exploit"]},{"url":"https://github.com/runZeroInc/vulns-2026-fatfs-chance","tags":["technical-description","exploit","Third Party Advisory","Exploit"]},{"url":"https://elm-chan.org/fsw/ff/","tags":["product","Product"]},{"url":"https://www.runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687/","tags":["third-party-advisory","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6687"},{"url":"https://elm-chan.org/fsw/ff"},{"url":"https://www.runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687"},{"url":"https://www.runzero.com/blog/fatfs-bugs"},{"url":"https://github.com/advisories/GHSA-wghw-hg6m-7rh3"}],"sources":{"cve":[{"id":"CVE-2026-6687","title":"FatFs Stack Buffer Overflow via Uncapped exFAT Label Length","description":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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.","status":"published","published":"2026-07-01T13:57:54.242Z","modified":"2026-07-01T15:06:24.705Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T13:50:04.986624Z"}],"euvd":[{"id":"EUVD-2026-40999","description":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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.","status":"published","published":"2026-07-01T13:57:54Z","modified":"2026-07-01T15:06:24Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T18:20:19.829772Z"}],"ghsa":[{"id":"GHSA-wghw-hg6m-7rh3","title":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length ...","description":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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.","status":"published","published":"2026-07-01T15:35:21Z","modified":"2026-07-01T15:35:27Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T15:09:08.409779Z"}],"nvd":[{"id":"CVE-2026-6687","description":"FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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.","status":"published","published":"2026-07-01T15:17:12.87Z","modified":"2026-10-25T17:10:00.197Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T14:12:27.199837Z"}]}}