---
id: CVE-2026-97906
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bootconfig: Fix integer overflow in initrd size check

  Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd
  with a huge bootconfig size (such as 0xF…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bootconfig: Fix integer overflow in initrd size check

  Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd
  with a huge bootconfig size (such as 0xF…
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'
cwe:
  - CWE-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= de462e5f10718517bacf2f84c8aa2804567ef7df <
    4d45bc0f8cdf606d5409b5f64a8a6609f6520c03
  - >-
    Linux >= de462e5f10718517bacf2f84c8aa2804567ef7df <
    8d4343a411eaa182d323ab5b149496416015f27d
  - >-
    Linux >= de462e5f10718517bacf2f84c8aa2804567ef7df <
    bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6
  - >-
    Linux >= de462e5f10718517bacf2f84c8aa2804567ef7df <
    7812d6dab0698001e50e8c2f901e17da3eb6f429
  - Linux 32394df25d8e46935b442b429d74b37885c4f092
  - Linux >= 5.6.14 < 5.7
  - Linux 5.7
published: '2026-09-25'
updated: '2026-10-03'
sourceUpdated: '2026-10-03T11:18:08.970'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97906'
references:
  - url: 'https://git.kernel.org/stable/c/4d45bc0f8cdf606d5409b5f64a8a6609f6520c03'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7812d6dab0698001e50e8c2f901e17da3eb6f429'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d4343a411eaa182d323ab5b149496416015f27d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97906.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-97906'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541104'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-97906'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97906'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97906.mbox
  - url: 'https://git.kernel.org/stable/c/97be05f33f79342ea65d9b99c9ad07a93b8eef5a'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00217
epssPercentile: 0.12034
cvssSource: vendor
ingestedAt: '2026-09-25T11:06:38.893Z'
---

## Overview

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

bootconfig: Fix integer overflow in initrd size check

Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd
with a huge bootconfig size (such as 0xFFFFFFFF) can cause the pointer
arithmetic:

    data = ((void *)hdr) - size;

to wrap around on 32-bit systems (or when pointer subtraction overflows).
Because data wraps around, the subsequent bounds check:

    if ((unsigned long)data < initrd_start)

evaluates to false, bypassing the check. The kernel then calls
xbc_calc_checksum(data, size), which attempts to read 4GB of memory,
hitting unmapped pages and triggering a fatal kernel page fault during
early boot. Furthermore, on 64-bit systems with an initrd > 4.29 GB, an
unbounded 32-bit size can similarly bypass the initrd_start check.

Fix this by:
1. Ensuring the initrd is at least large enough to contain the bootconfig
   footer and verifying hdr is within the initrd bounds.
2. Checking that size does not exceed XBC_DATA_MAX and does not exceed
   the available space between initrd_start and hdr before performing
   pointer subtraction.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97906.json)