CVE-2026-6683: medium-severity vulnerability in ChaN FatFs
FatFs Divide-by-Zero in exFAT Sync
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.6epss 0.3%
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.
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
ChaN · FatFsRelated CVEs — ChaN FatFs
In the same product, most dangerous first.
CVE-2026-6687HIGHFatFs Stack Buffer Overflow via Uncapped exFAT Label LengthEPSS 0.3%CVE-2026-6688HIGHFatFs Buffer Overflow via Unbounded LFN Filename CopyEPSS 0.3%CVE-2026-6682HIGHFatFs Integer Overflow in FAT32 Volume MountEPSS 0.3%CVE-2026-6684MEDIUMFatFs Infinite Loop in GPT Partition ScanEPSS 0.3%CVE-2026-6686MEDIUMFatFs Use of Uninitialized Clusters After Seek Past EOFEPSS 0.3%