---
id: CVE-2026-64427
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  HID: logitech-dj: Fix maxfield check in DJ short report validation

  Commit b6a57912854e ("HID: logitech-dj: Prevent REPORT_ID_DJ_SHORT
  related user initiated OOB write"…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  HID: logitech-dj: Fix maxfield check in DJ short report validation

  Commit b6a57912854e ("HID: logitech-dj: Prevent REPORT_ID_DJ_SHORT
  related user initiated OOB write"…
severity: none
published: '2026-07-25'
updated: '2026-08-09'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64427'
references:
  - url: 'https://git.kernel.org/stable/c/2b70bebc709489d29a31ac2935aeffb8d5228395'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/590cc4d782487632a52f37c2171bee1eeea29627'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7a89ad762fad53d56b7002d7ffc923a4b7f4006f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/80c1e18473f63fd7c6a2bc9ad6f3d0a6cc4fb500'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/95b3f23d632490b5eb285b9fcf7284f2ac8f9872'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00123
epssPercentile: 0.02326
ingestedAt: '2026-08-09T19:34:41.234Z'
---

## Overview

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

HID: logitech-dj: Fix maxfield check in DJ short report validation

Commit b6a57912854e ("HID: logitech-dj: Prevent REPORT_ID_DJ_SHORT
related user initiated OOB write") added validation for the DJ short
output report, but the error path dereferences rep->field[0] even when
rep->maxfield is zero.

Commit 8b9a097eb2fc ("HID: logitech-dj: fix wrong detection of bad
DJ_SHORT output report") made the check conditional on rep being present,
but a crafted descriptor can still create report ID 0x20 with only padding
output items. hid-core registers the report, ignores the padding field,
and leaves rep->maxfield as zero.

In that case the validation enters the rep->maxfield < 1 branch and then
dereferences rep->field[0]->report_count while printing the error message,
causing a NULL pointer dereference during probe. This is reproducible with
uhid by emulating a Logitech receiver with a padding-only DJ short output
report:

  BUG: KASAN: null-ptr-deref in logi_dj_probe+0xb1/0x754 [hid_logitech_dj]
  Read of size 4 at addr 0000000000000028 by task kworker/4:1/129
  ...
  Call Trace:
   logi_dj_probe+0xb1/0x754 [hid_logitech_dj]
   hid_device_probe+0x329/0x3f0 [hid]
   really_probe+0x162/0x570
   __device_attach+0x137/0x2c0
   bus_probe_device+0x38/0xc0
   device_add+0xa56/0xce0
   hid_add_device+0x19c/0x280 [hid]
   uhid_device_add_worker+0x2c/0xb0 [uhid]

Reject the zero-field report before printing the field report_count.

## Remediation

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