CVE-2026-6685

6.1 MEDIUM
Published: July 01, 2026 Modified: July 01, 2026
View on NVD

Description

FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write() (fp->sect - sect < cc) during interleaved read/write on fragmented filesystems. This maps to CWE-191 (Integer Underflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H (6.1, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://elm-chan.org/fsw/ff/
Source: 44488dab-36db-4358-99f9-bc116477f914
https://github.com/runZeroInc/vulns-2026-fatfs-chance
Source: 44488dab-36db-4358-99f9-bc116477f914
https://www.runzero.com/blog/fatfs-bugs/
Source: 44488dab-36db-4358-99f9-bc116477f914

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.1 / 10.0
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)