---
id: CVE-2026-91041
title: >-
  FileX fault-tolerant log replay writes past the destination sector when
  mounting a crafted FAT image
summary: >-
  Mounting an attacker-controlled FAT image with fault tolerance enabled causes
  an out-of-bounds heap write during log replay. The write is
  attacker-positioned and attacker-valued, and on a common embedded memory
  layout it reaches the FX_M…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-787
  - CWE-1284
vendor: Eclipse Foundation
product: FileX
affected:
  - FileX <= 6.5.1.202602
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-20T15:29:42.506041Z'
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T15:30:22.550Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-91041'
references:
  - url: >-
      https://github.com/eclipse-threadx/filex/security/advisories/GHSA-c8cj-fj9j-426v
tags:
  - cve.org
ingestedAt: '2026-10-20T14:08:00.578Z'
---

## Overview

Mounting an attacker-controlled FAT image with fault tolerance enabled causes an out-of-bounds heap write during log replay. The write is attacker-positioned and attacker-valued, and on a common embedded memory layout it reaches the FX_MEDIA driver callback, giving control of the instruction pointer.

## Affected

- `FileX <= 6.5.1.202602`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.