CVE-2026-6685

mediumCVSS 6.1covered by 1 sourcefirst seen 2026-07-01

FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp->sect - sect < cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). 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)

mediumCVE-2026-6685: FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_re…nvd · 2026-07-01

External references

NVD record for CVE-2026-6685

CVE.org record

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