---
id: CVE-2026-31624
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  HID: core: clamp report_size in s32ton() to avoid undefined shift

  s32ton() shifts by n-1 where n is the field's report_size, a value that
  comes directly from a HID dev…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  HID: core: clamp report_size in s32ton() to avoid undefined shift

  s32ton() shifts by n-1 where n is the field's report_size, a value that
  comes directly from a HID dev…
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'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.20.1, < 6.6.136'
  - 'linux_kernel >= 6.7, < 6.12.83'
  - 'linux_kernel >= 6.13, < 6.18.24'
  - 'linux_kernel >= 6.19, < 6.19.14'
  - 'linux_kernel >= 7.0, < 7.0.1'
  - linux_kernel = 2.6.20
patched:
  - linux_kernel 7.0.1
published: '2026-04-24'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:13.317'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31624'
references:
  - url: 'https://git.kernel.org/stable/c/0ab048dbdb1daacf17d52e9252297eb6e1298e49'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/58386f00af710922cafb0fb69211497beddfaa95'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/69c02ffde6ed4d535fa4e693a9e572729cad3d0d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/76ad02854a30c394e0c076e6e6bed0a388573a94'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8a8333237f1f5caab8d4c3d2c2e7578c4263a97f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/932ae5309e53561197aa7d1606c7cf63af10e24f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/97014719bb8fccb1ffcbbc299e84b1f11b114195'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ea363a34086ddb4231adc581a7f36c39ec154bfc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/eb415ddaf25e09ddb8fe5736a70c9de2e6462534'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00166
epssPercentile: 0.05477
ingestedAt: '2026-10-15T03:30:12.860Z'
---

## Overview

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

HID: core: clamp report_size in s32ton() to avoid undefined shift

s32ton() shifts by n-1 where n is the field's report_size, a value that
comes directly from a HID device.  The HID parser bounds report_size
only to <= 256, so a broken HID device can supply a report descriptor
with a wide field that triggers shift exponents up to 256 on a 32-bit
type when an output report is built via hid_output_field() or
hid_set_field().

Commit ec61b41918587 ("HID: core: fix shift-out-of-bounds in
hid_report_raw_event") added the same n > 32 clamp to the function
snto32(), but s32ton() was never given the same fix as I guess syzbot
hadn't figured out how to fuzz a device the same way.

Fix this up by just clamping the max value of n, just like snto32()
does.

## Affected

- `linux_kernel >= 2.6.20.1, < 6.6.136`
- `linux_kernel >= 6.7, < 6.12.83`
- `linux_kernel >= 6.13, < 6.18.24`
- `linux_kernel >= 6.19, < 6.19.14`
- `linux_kernel >= 7.0, < 7.0.1`
- `linux_kernel = 2.6.20`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.1`