CVE-2026-6685
FatFs Integer Underflow in Dirty-Sector Cache Flush
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.
INFO
Published Date :
July 1, 2026, 1:47 p.m.
Last Modified :
July 1, 2026, 2:10 p.m.
Remotely Exploit :
No
Source :
runZero
Affected Products
The following products are affected by CVE-2026-6685
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 44488dab-36db-4358-99f9-bc116477f914 |
Solution
- Update FatFs to a non-vulnerable version.
- Apply relevant patches for FatFs R0.16.
- Review filesystem access patterns.
Public PoC/Exploit Available at Github
CVE-2026-6685 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
CSS HTML C Dockerfile CMake Shell Python Go Makefile
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6685 vulnerability anywhere in the article.