---
id: CVE-2026-98403
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/boot: Avoid IPL parameter append past command line

  A command line may occupy all but the terminating byte of
  COMMAND_LINE_SIZE
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/boot: Avoid IPL parameter append past command line

  A command line may occupy all but the terminating byte of
  COMMAND_LINE_SIZE. In that case append_ipl_block_parm…
severity: none
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T14:17:51.383'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98403'
references:
  - url: 'https://git.kernel.org/stable/c/73eec5a0d55916d7e1115f5d03a7ffc06d6215cf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d11bfec8666f8409fac9072e9c25b691d3e30ac'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/af9866021a00ab9eeacf0c33ee73f3d134b4ed70'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d76181dfabdaa720703167393704efacba343442'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-14T15:36:13.981Z'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5ecb2da660ab8eddafe059a6a8a708465db89ca2 <
    af9866021a00ab9eeacf0c33ee73f3d134b4ed70
  - >-
    Linux >= 5ecb2da660ab8eddafe059a6a8a708465db89ca2 <
    73eec5a0d55916d7e1115f5d03a7ffc06d6215cf
  - >-
    Linux >= 5ecb2da660ab8eddafe059a6a8a708465db89ca2 <
    8d11bfec8666f8409fac9072e9c25b691d3e30ac
  - >-
    Linux >= 5ecb2da660ab8eddafe059a6a8a708465db89ca2 <
    d76181dfabdaa720703167393704efacba343442
  - Linux 5.16
---

## Overview

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

s390/boot: Avoid IPL parameter append past command line

A command line may occupy all but the terminating byte of
COMMAND_LINE_SIZE. In that case append_ipl_block_parm() passes a zero size
to the IPL parameter conversion helpers and points the destination one
byte past early_command_line. The helpers subtract one from the unsigned
size and write the converted parameter outside the command line buffer.

Convert the IPL parameter in the command line parsing buffer first. A
parameter beginning with '=' can then replace the existing command line
regardless of its length, while other parameters are appended only when
space remains.

## Remediation

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