Vulnerability in Chan Fatfs
CVE-2026-6684
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (21.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Chan Fatfs — versions 0
- Elm-Chan Fatfs
Weakness classification (CWE)
References
- 44488dab-36db-4358-99f9-bc116477f914 (Exploit, Third Party Advisory, third-party-advisory)
- 44488dab-36db-4358-99f9-bc116477f914 (Exploit, technical-description, Third Party Advisory)
- 44488dab-36db-4358-99f9-bc116477f914 (Product, product)
- 44488dab-36db-4358-99f9-bc116477f914 (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-6684?
- CVE-2026-6684 is a medium-severity vulnerability in Chan Fatfs, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 4.6/10. Published 2026-07-01.
- How severe is CVE-2026-6684?
- Medium severity. CVSS v3 base score is 4.6 out of 10.