CVE-2026-6684: medium-severity vulnerability in ChaN FatFs
FatFs Infinite Loop in GPT Partition Scan
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 prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). 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). 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-2026-6683MEDIUMFatFs Divide-by-Zero in exFAT SyncEPSS 0.3%CVE-2026-6686MEDIUMFatFs Use of Uninitialized Clusters After Seek Past EOFEPSS 0.3%