---
id: CVE-2025-68237
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mtdchar: fix integer overflow in read/write ioctls

  The "req.start" and "req.len" variables are u64 values that come from the
  user at the start of the function
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mtdchar: fix integer overflow in read/write ioctls

  The "req.start" and "req.len" variables are u64 values that come from the
  user at the start of the function.  We mas…
severity: none
published: '2025-12-16'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-68237'
references:
  - url: 'https://git.kernel.org/stable/c/37944f4f8199cd153fef74e95ca268020162f212'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/457376c6fbf0c69326a9bf1f72416225f681192b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e4185bed738da755b191aa3f2e16e8b48450e1b8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/eb9361484814fb12f3b7544b33835ea67d7a6a97'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f37efdd97fd1ec3e0d0f1eec279c8279e28f981e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00186
epssPercentile: 0.07601
ingestedAt: '2026-10-14T13:30:58.463Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

mtdchar: fix integer overflow in read/write ioctls

The "req.start" and "req.len" variables are u64 values that come from the
user at the start of the function.  We mask away the high 32 bits of
"req.len" so that's capped at U32_MAX but the "req.start" variable can go
up to U64_MAX which means that the addition can still integer overflow.

Use check_add_overflow() to fix this bug.

## Remediation

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