---
id: CVE-2025-38688
title: 'iommufd: Prevent ALIGN() overflow'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  iommufd: Prevent ALIGN() overflow

  When allocating IOVA the candidate range gets aligned to the target
  alignment. If the range is close to ULONG_MAX then the ALIGN() ca…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef <
    d19b817540c0abe84854a64ee9ee34cecc3bbeef
  - >-
    Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef <
    ebb6021560b94649bec6b8faba6fe0dca2218e81
  - >-
    Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef <
    e42a046bb41dcdde4f766a17d8211842007ed537
  - >-
    Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef <
    79fad1917802c28de51a479318a056a6fbe3e2f2
  - >-
    Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef <
    b42497e3c0e74db061eafad41c0cd7243c46436b
  - Linux 6.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:52:48.832507Z'
published: '2025-09-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:28.092Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-38688'
references:
  - url: 'https://git.kernel.org/stable/c/d19b817540c0abe84854a64ee9ee34cecc3bbeef'
  - url: 'https://git.kernel.org/stable/c/ebb6021560b94649bec6b8faba6fe0dca2218e81'
  - url: 'https://git.kernel.org/stable/c/e42a046bb41dcdde4f766a17d8211842007ed537'
  - url: 'https://git.kernel.org/stable/c/79fad1917802c28de51a479318a056a6fbe3e2f2'
  - url: 'https://git.kernel.org/stable/c/b42497e3c0e74db061eafad41c0cd7243c46436b'
tags:
  - cve.org
epss: 0.00169
epssPercentile: 0.06247
ingestedAt: '2026-10-15T22:48:25.517Z'
---

## Overview

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

iommufd: Prevent ALIGN() overflow

When allocating IOVA the candidate range gets aligned to the target
alignment. If the range is close to ULONG_MAX then the ALIGN() can
wrap resulting in a corrupted iova.

Open code the ALIGN() using get_add_overflow() to prevent this.
This simplifies the checks as we don't need to check for length earlier
either.

Consolidate the two copies of this code under a single helper.

This bug would allow userspace to create a mapping that overlaps with some
other mapping or a reserved range.

## Affected

- `Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef < d19b817540c0abe84854a64ee9ee34cecc3bbeef`
- `Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef < ebb6021560b94649bec6b8faba6fe0dca2218e81`
- `Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef < e42a046bb41dcdde4f766a17d8211842007ed537`
- `Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef < 79fad1917802c28de51a479318a056a6fbe3e2f2`
- `Linux >= 51fe6141f0f64ae0bbc096a41a07572273e8c0ef < b42497e3c0e74db061eafad41c0cd7243c46436b`
- `Linux 6.2`

## Remediation

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