PT-2026-54924 · Chan · Fatfs

Hd Moore + 2 · Published 2026-07-01 · Updated 2026-07-01 · CVE-2026-6682

Mitre

CVSS v3.1

7.6

High

Base vector

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

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.

Exploit

Fix

Integer Overflow

Weakness Enumeration

CWE-190

Related Identifiers

CVE-2026-6682

Affected Products

Fatfs

References · 5

• 🔥 https://github.com/runZeroInc/vulns-2026-fatfs-chance · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-6682 · Security Note
• https://elm-chan.org/fsw/ff · Note
• https://runzero.com/advisories/fatfs-fat32-int-of-mnt-cve-2026-6682 · Note
• https://runzero.com/blog/fatfs-bugs · Note