---
id: CVE-2026-89756
title: >-
  kernel: mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
  (CVE-2026-89756)
summary: >-
  A flaw was found in the Linux kernel. When performing memory migration on KVM
  (Kernel-based Virtual Machine) hosts, the `migrate_pages_batch()` function
  fails to report RCU (Read-Copy Update) tasks quiescent states during large
  batch unmap…
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-821
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T19:56:02+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89756.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89756.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89756'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532146'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89756'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89756'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89756.mbox
  - url: 'https://git.kernel.org/stable/c/4996a7bc01ef35570664854dac2530c604981039'
  - url: 'https://git.kernel.org/stable/c/5dc0daff0341c6baba19c38f47d299ac831d7e99'
  - url: 'https://git.kernel.org/stable/c/66734981b4d3c105223a13c827c9c73be18d91ad'
  - url: 'https://git.kernel.org/stable/c/efe8f86c0916f0f74eea74ae21a3b37f728c6bad'
  - url: 'https://git.kernel.org/stable/c/8c6d63d434ebb85c6cf3dac1e70a171b183c6614'
  - url: 'https://git.kernel.org/stable/c/4757542649af56d894e25e30f57cd497dffad53f'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00191
epssPercentile: 0.09088
ingestedAt: '2026-09-14T15:23:07.448Z'
---

## Overview

A flaw was found in the Linux kernel. When performing memory migration on KVM (Kernel-based Virtual Machine) hosts, the `migrate_pages_batch()` function fails to report RCU (Read-Copy Update) tasks quiescent states during large batch unmapping operations. This oversight causes the migrating task to become an RCU holdout, leading to a prolonged stall in the RCU grace period. This can result in a Denial of Service (DoS) by keeping the CPU busy for an extended duration.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89756.json)

**kernel: mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 7

## Remediation

Out of support scope