PT-2026-54926 · Chan · Fatfs

Hd Moore + 1 · Published 2026-07-01 · Updated 2026-07-01 · CVE-2026-6684

NVD

CVSS v3.1

4.6

Medium

Base vector

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

FatFs prior to R0.16 that use GPT scanning with 'FF LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.

Exploit

Fix

Infinite Loop

Weakness Enumeration

CWE-835

Related Identifiers

CVE-2026-6684

Affected Products

Fatfs

References · 5

• 🔥 https://github.com/runZeroInc/vulns-2026-fatfs-chance · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-6684 · Security Note
• https://runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684 · Note
• https://elm-chan.org/fsw/ff · Note
• https://runzero.com/blog/fatfs-bugs · Note