CVE & CISA-KEV Catalog

CVE-2026-6686

MEDIUM
4.6
CVSS v3
NVD

Description

FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.

CWE-908

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorPhysical
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityNone
AvailabilityNone

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

Exploit Intelligence

EPSS data unavailable for this CVE.

References

Embed a live status badge for CVE-2026-6686
CVE-2026-6686 severity badge

Markdown

[![CVE-2026-6686](https://tridentstack.com/cve/badge/CVE-2026-6686.svg)](https://tridentstack.com/cve/CVE-2026-6686)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-6686"><img src="https://tridentstack.com/cve/badge/CVE-2026-6686.svg" alt="CVE-2026-6686"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-01.