---
id: CVE-2026-98821
title: 'kernel: block: reject polled dio with user integrity metadata (CVE-2026-98821)'
summary: >-
  A flaw was found in the Linux kernel's block layer. A local user could exploit
  this vulnerability to cause a denial of service (DoS) by initiating polled
  direct I/O operations combined with user integrity metadata. Because the
  kernel impro…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-843
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: '2026-10-23'
sourceUpdated: '2026-10-23T20:15:38+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98821.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98821.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98821'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555239'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98821'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98821'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98821.mbox
  - url: 'https://git.kernel.org/stable/c/c97ef13ad96be0e08af38dfa2ed40cded0b53e1b'
  - url: 'https://git.kernel.org/stable/c/dd33c03cefccdfcb223e9e6262643d64f8c1ae20'
  - url: 'https://git.kernel.org/stable/c/2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00166
epssPercentile: 0.05792
ingestedAt: '2026-10-18T16:47:32.474Z'
---

## Overview

A flaw was found in the Linux kernel's block layer. A local user could exploit this vulnerability to cause a denial of service (DoS) by initiating polled direct I/O operations combined with user integrity metadata. Because the kernel improperly attempts to poll integrity metadata as standard block I/O request structures, an invalid pointer dereference occurs, resulting in a system crash.

## 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 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98821.json)

**kernel: block: reject polled dio with user integrity metadata** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-23.

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