Saint FatFs Chance

Technical record

Disclosed on

July 1 2026

CVE

CVE-2026-6682CVE-2026-6683CVE-2026-6684CVE-2026-6685CVE-2026-6686CVE-2026-6687CVE-2026-6688

CVSS

7.6

Product

ChaN · FatFs

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.

Sources: runzero.com · github.com