---
id: CVE-2025-21863
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  io_uring: prevent opcode speculation

  sqe->opcode is used for different tables, make sure we santitise it
  against speculations.
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  io_uring: prevent opcode speculation

  sqe->opcode is used for different tables, make sure we santitise it
  against speculations.
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'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.6, < 6.6.80'
  - 'linux_kernel >= 6.7, < 6.12.17'
  - 'linux_kernel >= 6.13, < 6.13.5'
  - linux_kernel = 6.14
patched:
  - linux_kernel 6.13.5
published: '2025-03-12'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T09:17:26.527'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21863'
references:
  - url: 'https://git.kernel.org/stable/c/18eae8420081ef8e043ad455937bfb470ef08607'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1e988c3fe1264708f4f92109203ac5b1d65de50b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/506b9b5e8c2d2a411ea8fe361333f5081c56d23a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/87e9eef43c758da267f6332678058a79764c7eba'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b9826e3b26ec031e9063f64a7c735449c43955e4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d261ead565a080e3411b0dd04e6d58a52471cac8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fdbfd52bd8b85ed6783365ff54c82ab7067bd61b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2025-10-01T19:25:38.400104Z'
epss: 0.00233
epssPercentile: 0.12626
ingestedAt: '2026-09-08T09:30:06.186Z'
---

## Overview

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

io_uring: prevent opcode speculation

sqe->opcode is used for different tables, make sure we santitise it
against speculations.

## Affected

- `linux_kernel >= 5.6, < 6.6.80`
- `linux_kernel >= 6.7, < 6.12.17`
- `linux_kernel >= 6.13, < 6.13.5`
- `linux_kernel = 6.14`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.13.5`