Buffer overflow in Chan Fatfs
CVE-2026-6687
FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.
Vulnerability class: Buffer Overflow
EPSS: 0.005 (37.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
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-2026-6687?
- CVE-2026-6687 is a high-severity vulnerability in Chan Fatfs, classified under Stack-based Buffer Overflow. CVSS score: 7.6/10. Published 2026-07-01.
- How severe is CVE-2026-6687?
- High severity. CVSS v3 base score is 7.6 out of 10.