---
id: CVE-2025-40216
title: 'io_uring/rsrc: don''t rely on user vaddr alignment'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  io_uring/rsrc: don't rely on user vaddr alignment

  There is no guaranteed alignment for user pointers, however the
  calculation of an offset of the first page into a fol…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d <
    50998b0ae7d9d552e96d8b7239981cf05f65eff5
  - >-
    Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d <
    f16769241594be59387b56ab525e327f54377e60
  - >-
    Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d <
    3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b
  - Linux 6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:58:17.038442Z'
published: '2025-12-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:41.119Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-40216'
references:
  - url: 'https://git.kernel.org/stable/c/50998b0ae7d9d552e96d8b7239981cf05f65eff5'
  - url: 'https://git.kernel.org/stable/c/f16769241594be59387b56ab525e327f54377e60'
  - url: 'https://git.kernel.org/stable/c/3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b'
tags:
  - cve.org
epss: 0.00142
epssPercentile: 0.03116
ingestedAt: '2026-10-15T22:48:25.552Z'
---

## Overview

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

io_uring/rsrc: don't rely on user vaddr alignment

There is no guaranteed alignment for user pointers, however the
calculation of an offset of the first page into a folio after coalescing
uses some weird bit mask logic, get rid of it.

## Affected

- `Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d < 50998b0ae7d9d552e96d8b7239981cf05f65eff5`
- `Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d < f16769241594be59387b56ab525e327f54377e60`
- `Linux >= a8edbb424b1391b077407c75d8f5d2ede77aa70d < 3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b`
- `Linux 6.12`

## Remediation

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