---
id: CVE-2026-89568
title: >-
  kernel: kho: fix size calculation in kho_preserved_memory_reserve()
  (CVE-2026-89568)
summary: >-
  A flaw was found in the Linux kernel. The `kho_preserved_memory_reserve()`
  function, responsible for reserving memory, incorrectly calculates the size of
  these reservations. This issue arises because it uses a 32-bit integer for bit
  shifti…
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-1335
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T22:07:22+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89568'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532296'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89568'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89568'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89568.mbox
  - url: 'https://git.kernel.org/stable/c/3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded'
  - url: 'https://git.kernel.org/stable/c/42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00198
epssPercentile: 0.08463
ingestedAt: '2026-09-14T11:11:19.886Z'
---

## Overview

A flaw was found in the Linux kernel. The `kho_preserved_memory_reserve()` function, responsible for reserving memory, incorrectly calculates the size of these reservations. This issue arises because it uses a 32-bit integer for bit shifting, which limits the maximum reservation size to 2 Gigabytes (GiB). Consequently, attempts to reserve memory larger than 2 GiB can lead to undefined behavior, potentially causing system instability or a denial of service.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json)

**kernel: kho: fix size calculation in kho_preserved_memory_reserve()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

Not affected:

- Red Hat Enterprise Linux 10
- 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

Refer to the advisory for fix availability.