CVE-2026-6682 HIGH

CVE-2026-6682: FatFs Integer Overflow in FAT32 Volume Mount

Vendor Chan
Product FatFs
Weakness CWE-190
Published July 1, 2026
Last update July 1, 2026

CVSS base score

7.6/10
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

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