---
id: CVE-2026-98858
title: >-
  kernel: io_uring: fix task_work add use-after-free with SQPOLL
  (CVE-2026-98858)
summary: >-
  A flaw was found in the Linux kernel's io_uring subsystem. When submission
  queue polling (SQPOLL) is enabled, a race condition can cause the polling
  thread to free the ring context while another operation is still accessing it.
  A local use…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-825
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-10-18'
updated: '2026-10-24'
sourceUpdated: '2026-10-24T06:18:05+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98858.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98858.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98858'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555237'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98858'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98858'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98858.mbox
  - url: 'https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e'
  - url: 'https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c'
  - url: 'https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3'
  - url: 'https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00157
epssPercentile: 0.04763
ingestedAt: '2026-10-18T16:47:32.461Z'
---

## Overview

A flaw was found in the Linux kernel's io_uring subsystem. When submission queue polling (SQPOLL) is enabled, a race condition can cause the polling thread to free the ring context while another operation is still accessing it. A local user can exploit this use-after-free flaw to crash the system, resulting in a Denial of Service (DoS), or potentially achieve privilege escalation.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98858.json)

**kernel: io_uring: fix task_work add use-after-free with SQPOLL** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-24.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Fix deferred