Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Elm-Chan | Fatfs | <= r0.16 |
Related Weaknesses (CWE)
References
- https://elm-chan.org/fsw/ff/Product
- https://github.com/runZeroInc/vulns-2026-fatfs-chanceThird Party AdvisoryExploit
- https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683Third Party Advisory
- https://www.runzero.com/blog/fatfs-bugs/Third Party AdvisoryExploit
- https://github.com/runZeroInc/vulns-2026-fatfs-chanceThird Party AdvisoryExploit
FAQ
What is CVE-2026-6683?
CVE-2026-6683 is a vulnerability with a CVSS score of 4.6 (MEDIUM). 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). Esti...
How severe is CVE-2026-6683?
CVE-2026-6683 has been rated MEDIUM with a CVSS base score of 4.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-6683?
Check the references section above for vendor advisories and patch information. Affected products include: Elm-Chan Fatfs.