---
id: CVE-2026-98400
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/ipl: Fix NULL deref in kdump without re-IPL parm block

  Some IPL types, like HMC FTP boot or QEMU direct kernel boot, might
  not provide an IPL parameter block
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/ipl: Fix NULL deref in kdump without re-IPL parm block

  Some IPL types, like HMC FTP boot or QEMU direct kernel boot, might
  not provide an IPL parameter block. In …
severity: none
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T14:17:51.010'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98400'
references:
  - url: 'https://git.kernel.org/stable/c/030e88812435fc5d6aa42eee41fa77b5ea620327'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-14T15:36:13.980Z'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3b9678472bab86ae654cf2c18d5dd551558045be <
    030e88812435fc5d6aa42eee41fa77b5ea620327
  - >-
    Linux >= 3b9678472bab86ae654cf2c18d5dd551558045be <
    92d0829eae257544b6b0faccb6e7079c45e22d48
  - >-
    Linux >= 3b9678472bab86ae654cf2c18d5dd551558045be <
    50f9c40768e84f30d374235b3ee3850a94d9ac29
  - >-
    Linux >= 3b9678472bab86ae654cf2c18d5dd551558045be <
    b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd
  - >-
    Linux >= 3b9678472bab86ae654cf2c18d5dd551558045be <
    7f918871112e8e7c581e99eb8e545af4e59c8367
  - Linux 4.17
---

## Overview

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

s390/ipl: Fix NULL deref in kdump without re-IPL parm block

Some IPL types, like HMC FTP boot or QEMU direct kernel boot, might
not provide an IPL parameter block. In this case, reipl_type_init()
selects IPL_TYPE_UNKNOWN, and reipl_block_actual remains NULL.

kdump passes the re-IPL parameter block to the dump kernel through
os_info. Before commit 3b9678472bab ("s390/ipl: correct kdump reipl
block checksum calculation"), the os_info entry was added only for
IPL types which initialized reipl_block_actual. That commit moved the
os_info update to machine_crash_shutdown(), making it unconditional. As
a result, set_os_info_reipl_block() dereferences reipl_block_actual for
IPL_TYPE_UNKNOWN. This may happen to work by chance when address zero
contains readable lowcore data and the resulting empty os_info entry is
ignored by the dump kernel.

Skip the os_info update when no re-IPL parameter block is available.
Kdump then collect the dump and reboot without setting re-IPL parameter
block.

## Remediation

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