Description
FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). 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.
Published: 2026-07-01
Score: 7.6 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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History

Mon, 06 Jul 2026 23:15:00 +0000

Type Values Removed Values Added
First Time appeared Chan
Chan fatfs
Vendors & Products Chan
Chan fatfs

Wed, 01 Jul 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 01 Jul 2026 14:30:00 +0000

Type Values Removed Values Added
Description FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). 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.
Title FatFs Buffer Overflow via Unbounded LFN Filename Copy
Weaknesses CWE-120
References
Metrics cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: runZero

Published:

Updated: 2026-07-01T15:06:59.026Z

Reserved: 2026-04-20T15:06:24.308Z

Link: CVE-2026-6688

cve-icon Vulnrichment

Updated: 2026-07-01T15:06:47.991Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-07T15:00:06Z

Weaknesses