---
id: CVE-2026-97480
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tty: serial: 8250: protect against NULL uart->port.dev in register

  serial8250_register_8250_port() conditionally copies uart->port.dev
  from up->port.dev only when up->…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tty: serial: 8250: protect against NULL uart->port.dev in register

  serial8250_register_8250_port() conditionally copies uart->port.dev
  from up->port.dev only when up->…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    5cbab666721d974bfe033a12045d808936deaefd
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    941c9f84c9b6310f7aaa1c8c785dcc634ee33050
  - Linux < 6.18.53
  - Linux (all versions)
published: '2026-09-24'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T17:17:25.467'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97480'
references:
  - url: 'https://git.kernel.org/stable/c/5cbab666721d974bfe033a12045d808936deaefd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/941c9f84c9b6310f7aaa1c8c785dcc634ee33050'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T16:47:15.871Z'
---

## Overview

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

tty: serial: 8250: protect against NULL uart->port.dev in register

serial8250_register_8250_port() conditionally copies uart->port.dev
from up->port.dev only when up->port.dev is non-NULL:

	if (up->port.dev) {
		uart->port.dev = up->port.dev;
		...
	}

So if both the existing uart slot and up have a NULL ->dev,
uart->port.dev remains NULL. The very next ACPI companion check
then dereferences it unconditionally:

	if (!has_acpi_companion(uart->port.dev)) {

has_acpi_companion() reads dev->fwnode without a NULL guard
(include/linux/acpi.h), so this NULL-derefs the kernel for the
remaining no-dev case rather than just skipping the
mctrl_gpio_init() initialisation as intended.

smatch flags the inconsistency:

  drivers/tty/serial/8250/8250_core.c:767
  serial8250_register_8250_port() error: 'uart->port.dev' could be
  null (see line 719)

Guard the call with a NULL check so register continues to work
for callers that legitimately have no parent device (legacy
non-OF/non-ACPI registrations).

No functional change for callers that pass a non-NULL ->dev.

## Remediation

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