CVE-2026-6684 | FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = … | CVSS 4.6 MEDIUM

Description

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.

Metadata

CVE ID: CVE-2026-6684
State: PUBLISHED
Assigner: runZero
Reserved: 2026-04-20 15:06 UTC
Published: 2026-07-01 13:45 UTC
Last updated: 2026-07-01 15:25 UTC
Primary CWE: CWE-835
CWE-835 Loop with unreachable exit condition ('infinite loop…
Vendor / Product: ChaN / FatFs
Sources: cve.org · NVD

Severity & Metrics

4.6 MEDIUM CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
ChaN	FatFs	—	0 < R0.16

Weakness (CWE)

CWE	Source	Description
CWE-835	cna	CWE-835 Loop with unreachable exit condition ('infinite loop')

CVSS scores (1)

Score	Severity	Version	Source	Vector
4.6	MEDIUM	3.1	cna	CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (4)