CVE-2026-6684

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.

CVSS v3 4.6 MEDIUM

4.6^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 0.9 / Impact : 3.6

Attack Vector PHYSICAL

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://elm-chan.org/fsw/ff/	Product
https://github.com/runZeroInc/vulns-2026-fatfs-chance	Third Party Advisory Exploit
https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/	Third Party Advisory
https://www.runzero.com/blog/fatfs-bugs/	Third Party Advisory Exploit
https://github.com/runZeroInc/vulns-2026-fatfs-chance	Third Party Advisory Exploit

Configurations

Configuration 1 (hide)

cpe:2.3:a:elm-chan:fatfs:*:*:*:*:*:*:*:*

History

25 Oct 2026, 17:10

Type	Values Removed	Values Added
Summary		(es) FatFs anterior a R0.16 que utiliza el escaneo GPT con ’FF_LBA64 = 1’ contiene un problema donde un conteo de bucle ilimitado derivado del campo de encabezado GPT GPTH_PtNum, lo que permite escaneos en tiempo de montaje extremadamente largos o efectivamente infinitos. Esto se mapea a CWE-835 (Bucle con Condición de Salida Inalcanzable). Vector CVSS v3.1 estimado: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Media). Los vectores SSVC de CISA estimados son Explotación: PoC, Impacto Técnico: Parcial.

Information

Published : 2026-07-01 15:17

Updated : 2026-10-25 17:10

NVD link : CVE-2026-6684

Mitre link : CVE-2026-6684

CVE.ORG link : CVE-2026-6684

JSON object : View

Products Affected

elm-chan

fatfs

CWE

CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')

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