---
id: CVE-2024-43819
title: 'kvm: s390: Reject memory region operations for ucontrol VMs'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  kvm: s390: Reject memory region operations for ucontrol VMs

  This change rejects the KVM_SET_USER_MEMORY_REGION and
  KVM_SET_USER_MEMORY_REGION2 ioctls when called on a …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 <
    705a8b8cc5a44b206096abb1bfdc8bc43b3c75c7
  - >-
    Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 <
    49c9945c054df4c22008e2bf87ca74d3e2507aa6
  - >-
    Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 <
    7816e58967d0e6cadce05c8540b47ed027dc2499
  - Linux 3.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2024-09-10T16:09:06.730085Z'
published: '2024-08-17'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:35:06.684Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2024-43819'
references:
  - url: 'https://git.kernel.org/stable/c/705a8b8cc5a44b206096abb1bfdc8bc43b3c75c7'
  - url: 'https://git.kernel.org/stable/c/49c9945c054df4c22008e2bf87ca74d3e2507aa6'
  - url: 'https://git.kernel.org/stable/c/7816e58967d0e6cadce05c8540b47ed027dc2499'
tags:
  - cve.org
epss: 0.00287
epssPercentile: 0.21069
ingestedAt: '2026-10-21T12:48:53.733Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

kvm: s390: Reject memory region operations for ucontrol VMs

This change rejects the KVM_SET_USER_MEMORY_REGION and
KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM.
This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and
would thus result in a null pointer dereference further in.
Memory management needs to be performed in userspace and using the
ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION
and KVM_SET_USER_MEMORY_REGION2.

[frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]

## Affected

- `Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 < 705a8b8cc5a44b206096abb1bfdc8bc43b3c75c7`
- `Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 < 49c9945c054df4c22008e2bf87ca74d3e2507aa6`
- `Linux >= 27e0393f15fc8bc855c6a888387ff5ffd2181089 < 7816e58967d0e6cadce05c8540b47ed027dc2499`
- `Linux 3.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.