CVE-2026-6683

MediumCVSS 4.6

Published: 01/07/2026(UTC)Updated: 02/07/2026(UTC)Translated: 03/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.19%

8th percentile — higher than 8% of all known CVEs

Summary

FatFs R0.16 and earlier contains a divide-by-zero bug in exFAT sync logic. Crafted metadata can cause n_fatent - 2 to be zero during write/sync operations, leading to a system crash.

Risk Assessment

An attacker with physical access can cause a denial of service (DoS). In network-delivered update scenarios, the attack can be remote, increasing risk for embedded and IoT systems.

Recommendation

Update FatFs to a version newer than R0.16 that fixes this bug. Restrict access to data media and monitor write/sync operations in critical systems.

Original NVD description (English source)

FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.