PT-2026-54929 · Chan · Fatfs

Hd Moore + 1 · Published 2026-07-01 · Updated 2026-07-01 · CVE-2026-6687

NVD

CVSS v3.1

7.6

High

Base vector

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

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.

Exploit

Fix

Stack Overflow

Weakness Enumeration

CWE-121

Related Identifiers

CVE-2026-6687

Affected Products

Fatfs

References · 5

• 🔥 https://github.com/runZeroInc/vulns-2026-fatfs-chance · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-6687 · Security Note
• https://elm-chan.org/fsw/ff · Note
• https://runzero.com/blog/fatfs-bugs · Note
• https://runzero.com/advisories/fatfs-exfat-label-len-of-cve-2026-6687 · Note