---
id: CVE-2026-98820
title: 'kernel: blk-mq: set RQF_USE_SCHED when the operation is known (CVE-2026-98820)'
summary: >-
  A flaw was found in the Linux kernel's block multi-queue (blk-mq) subsystem.
  When cached input/output (I/O) requests originally allocated for passthrough
  commands are reused for standard read or write operations, scheduler flags are
  not pr…
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-772
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: '2026-10-23T20:09:46+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98820.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98820.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98820'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555238'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98820'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98820'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98820.mbox
  - url: 'https://git.kernel.org/stable/c/790730e4d95de8356a573d4b4864486bba731863'
  - url: 'https://git.kernel.org/stable/c/2c47ebc27fa72078e26177cd458cdaf3006a9685'
  - url: 'https://git.kernel.org/stable/c/ab6c756f28c741d704a7c3e04814bfc3adf6f818'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00206
epssPercentile: 0.1063
ingestedAt: '2026-10-18T16:47:32.475Z'
---

## Overview

A flaw was found in the Linux kernel's block multi-queue (blk-mq) subsystem. When cached input/output (I/O) requests originally allocated for passthrough commands are reused for standard read or write operations, scheduler flags are not properly updated. This failure bypasses required scheduler initialization and cleanup routines, leading to internal resource leaks in certain I/O schedulers like Kyber. A local attacker could exploit this flaw to stall storage queues, resulting in a Denial of Service (DoS).

## 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-2026-98820.json)

**kernel: blk-mq: set RQF_USE_SCHED when the operation is known** — 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 OpenShift Container Platform 4

## Remediation

Fix deferred