PT-2026-54927 · Fatfs · Fatfs

Hd Moore

+2

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Published

2026-07-01

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Updated

2026-07-06

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CVE-2026-6685

CVSS v3.1

6.1

Medium

VectorAV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Name of the Vulnerable Software and Affected Versions FatFs versions R0.16 and earlier
Description An integer underflow occurs during interleaved read and write operations on fragmented filesystems. This issue is caused by an unsigned-subtraction wrap in the f read() and f write() functions when evaluating the condition fp->sect - sect < cc, which leads to a stale dirty-cache skip.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Integer Underflow

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Weakness Enumeration

Related Identifiers

CVE-2026-6685

Affected Products

Fatfs