CVE-2026-6682

Published: Jul 1, 2026Modified: Jul 2, 2026

7.6

Vector

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

Exploitability: 0.9 / Impact: 6.0

Source: 44488dab-36db-4358-99f9-bc116477f914 (Secondary)

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.

Affected (1)

Products: Elm Chan: Fatfs

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Elm Chan Fatfs	Up to r0.16

Related CWEs

Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

References (5)

https://elm-chan.org/fsw/ff/

Source: 44488dab-36db-4358-99f9-bc116477f914

Product

https://github.com/runZeroInc/vulns-2026-fatfs-chance

Source: 44488dab-36db-4358-99f9-bc116477f914

Third Party AdvisoryExploit

https://www.runzero.com/advisories/fatfs-fat32-int-of-mnt-cve-2026-6682/

Source: 44488dab-36db-4358-99f9-bc116477f914

Third Party AdvisoryExploit

https://www.runzero.com/blog/fatfs-bugs/

Source: 44488dab-36db-4358-99f9-bc116477f914

Third Party AdvisoryExploit

https://github.com/runZeroInc/vulns-2026-fatfs-chance

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Third Party AdvisoryExploit

Timeline

No history available yet.