---
id: CVE-2025-40293
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  iommufd: Don't overflow during division for dirty tracking

  If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
  to 0 and this triggers divide by…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  iommufd: Don't overflow during division for dirty tracking

  If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
  to 0 and this triggers divide by…
severity: none
published: '2025-12-08'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T22:10:00.210'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-40293'
references:
  - url: 'https://git.kernel.org/stable/c/07105e61882ff4a7d58db63cc5f9e90c6c60506c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4c8a4f1d34eced168cc0b3a3dfe7b6dcc2090f69'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cb30dfa75d55eced379a42fd67bd5fb7ec38555e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dbf316fc90aa954dcd5440817f4b944627ed63e0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/de7f2c67ceb1941b05b04ac35458a03e93cc57b1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00201
epssPercentile: 0.09314
ingestedAt: '2026-10-14T23:00:02.016Z'
---

## Overview

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

iommufd: Don't overflow during division for dirty tracking

If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
to 0 and this triggers divide by 0.

In this case the index should just be 0, so reorganize things to divide
by shift and avoid hitting any overflows.

## Remediation

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