---
id: CVE-2026-89921
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: s390: Zero initialize data structures for inject_pfault_token

  __kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of
  the on-stack struct kvm_s390_i…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: s390: Zero initialize data structures for inject_pfault_token

  __kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of
  the on-stack struct kvm_s390_i…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 383d0b050106abecb82f43101cac94fa423af5cd <
    9b046de62b8098af6e2ba820b125ec9dc5f162c8
  - >-
    Linux >= 383d0b050106abecb82f43101cac94fa423af5cd <
    134f235e0e8de54611a72d3cc3f63e5f31246baa
  - >-
    Linux >= 383d0b050106abecb82f43101cac94fa423af5cd <
    4e2c7f7cbc27418f9a290399b986c1b85ff93b90
  - Linux 3.19
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T11:17:01.173'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89921'
references:
  - url: 'https://git.kernel.org/stable/c/134f235e0e8de54611a72d3cc3f63e5f31246baa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4e2c7f7cbc27418f9a290399b986c1b85ff93b90'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9b046de62b8098af6e2ba820b125ec9dc5f162c8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:53.972Z'
epss: 0.00206
epssPercentile: 0.09523
---

## Overview

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

KVM: s390: Zero initialize data structures for inject_pfault_token

__kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of
the on-stack struct kvm_s390_irq but the full ext substructure is copied
into the cpu local variable on inject. ext_params and pad contain stale
stack values.

Interrupt delivery only uses ext_params2, so nothing leaks to the guest,
but a host user can use the migration ioctls to get to the data.

Fix by zero-initializing the irq struct.
Do the same for the inti data structure.

## Remediation

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