CVE-2026-6687

high

Description

FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). 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). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

References

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

https://www.runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687/

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

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

Details

Source: Mitre, NVD

Published: 2026-07-01

Updated: 2026-07-01

Risk Information

CVSS v2

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.6

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

Severity: High