CVE-2026-6686EPSS p30.9%

CVE-2026-6686CVE-2026-6686

elm-chan / fatfs

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.

Scoring

CVSS 4.6 ()
VectorCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS0.38% probability of exploitation · percentile 30.9% · 2026-08-15T12:02:44Z
Last modified2026-07-02
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.