CVE-2026-6682 | In FatFS R0.16 and earlier contains a FAT32 integer overflow… | CVSS 7.6 HIGH

Description

In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs->n_fats can wrap, leading to attacker-controlled file-size metadata and unsafe read lengths in downstream callers. This maps to CWE-190 (Integer Overflow or Wraparound). 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). Remote delivery is also possible in OTA/update pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

Metadata

CVE ID: CVE-2026-6682
State: PUBLISHED
Assigner: runZero
Reserved: 2026-04-20 15:06 UTC
Published: 2026-07-01 13:36 UTC
Last updated: 2026-07-01 15:24 UTC
Primary CWE: CWE-190
CWE-190 Integer overflow or wraparound
Vendor / Product: ChaN / FatFs
Sources: cve.org · NVD

Severity & Metrics

7.6 HIGH CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: no
Tech. Impact: total

Affected products (1)

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

Weakness (CWE)

CWE	Source	Description
CWE-190	cna	CWE-190 Integer overflow or wraparound

CVSS scores (1)

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

References (4)