CVE-2026-6687CWE-121

FatFs Stack Buffer Overflow via Uncapped exFAT Label Length

High · published July 1, 2026

CVSS v3.1
7.6
EPSS
0%
Percentile
27.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.6 · HIGH
Vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00348 · 27.2th percentile
Weakness
CWE-121 · Stack-based Buffer Overflow
Published
2026-07-01T13:57Z
EPSS history
Timeline
  • 01 JUL 13:57Z
    FatFs Stack Buffer Overflow via Uncapped exFAT Label Length
    cvelistv5