CVE-2026-6686 (GCVE-0-2026-6686)

Vulnerability from cvelistv5 – Published: 2026-07-01 13:55 – Updated: 2026-07-01 15:05
VLAI?
Title
FatFs Use of Uninitialized Clusters After Seek Past EOF
Summary
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.
Severity ?
4.6 (Medium)
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
  • CWE-908 - Use of uninitialized resource
Assigner
References
Impacted products
Vendor Product Version
ChaN FatFs Affected: 0 , ≤ R0.16 (custom)
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Credits
HD Moore of runZero, Inc. Tod Beardsley of runZero, Inc.
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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