PT-2026-54925 · Chan · Fatfs

Hd Moore + 1 · Published 2026-07-01 · Updated 2026-07-01 · CVE-2026-6683

Mitre

CVSS v3.1

4.6

Medium

Base vector

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

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.

Exploit

Fix

Divide By Zero

Weakness Enumeration

CWE-369

Related Identifiers

CVE-2026-6683

Affected Products

Fatfs

References · 5

• 🔥 https://github.com/runZeroInc/vulns-2026-fatfs-chance · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-6683 · Security Note
• https://elm-chan.org/fsw/ff · Note
• https://runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683 · Note
• https://runzero.com/blog/fatfs-bugs · Note