CVE-2026-6683 | FatFs R0.16 and earlier contains a divide-by-zero in exFAT s… | CVSS 4.6 MEDIUM

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.

Metadata

CVE ID: CVE-2026-6683
State: PUBLISHED
Assigner: runZero
Reserved: 2026-04-20 15:06 UTC
Published: 2026-07-01 13:41 UTC
Last updated: 2026-07-01 15:24 UTC
Primary CWE: CWE-369
CWE-369 Divide by zero
Vendor / Product: ChaN / FatFs
Sources: cve.org · NVD

Severity & Metrics

4.6 MEDIUM CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
ChaN	FatFs	—	0 ≤ R0.16

Weakness (CWE)

CWE	Source	Description
CWE-369	cna	CWE-369 Divide by zero

CVSS scores (1)

Score	Severity	Version	Source	Vector
4.6	MEDIUM	3.1	cna	CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (4)