CVE-2026-6683 MEDIUM

CVE-2026-6683: FatFs Divide-by-Zero in exFAT Sync

Vendor Chan
Product FatFs
Weakness CWE-369
Published July 1, 2026
Last update July 1, 2026
View on NVD All CVEs

CVSS base score

4.6/10
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 1, 2026 CVE published
July 1, 2026 Record updated