CVE-2026-6684 MEDIUM

CVE-2026-6684: FatFs Infinite Loop in GPT Partition Scan

Vendor Chan
Product FatFs
Weakness CWE-835
Published July 1, 2026
Last update July 1, 2026

CVSS base score

4.6/10
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 1, 2026 CVE published
July 1, 2026 Record updated