CVE-2026-6688

highCVSS 7.6covered by 1 sourcefirst seen 2026-07-01

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.

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Exploitation outlook

Low exploitation risk0.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 11% of all EPSS-scored CVEs.

Advisory coverage (1)

highCVE-2026-6688: FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatF…nvd · 2026-07-01

External references

NVD record for CVE-2026-6688

CVE.org record

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