CVE-2026-97480

Received Received - Intake

NULL Pointer Dereference in Linux Kernel Serial 8250 Driver

Publication date: 2026-09-24

Last updated on: 2026-09-28

Assigner: kernel.org

Description

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.

CVSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-09-28

Generated

2026-10-15

AI Q&A

2026-09-24

EPSS Evaluated

2026-10-13

NVD

CVE-2026-97480

EUVD

EUVD-2026-86078

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a NULL pointer dereference vulnerability in the Linux kernel's serial port driver. It occurs when the uart->port.dev field is NULL and the code attempts to check for an ACPI companion without first verifying if the device pointer is valid. This leads to a kernel crash.

Detection Guidance

This vulnerability is specific to the Linux kernel's serial driver and does not have network-based detection methods. It requires kernel-level inspection. Check if your kernel version includes the vulnerable code path by examining the serial8250_register_8250_port function in the 8250_core.c file. Look for missing NULL checks on uart->port.dev before calling has_acpi_companion().

Impact Analysis

If exploited, this vulnerability could cause a system crash or kernel panic, leading to denial of service. Systems relying on serial ports for critical functions may become unresponsive.

Compliance Impact

This vulnerability is a kernel-level NULL pointer dereference in the Linux serial driver. It does not directly relate to data protection, privacy, or security controls required by standards like GDPR or HIPAA. The issue affects system stability and could cause kernel crashes during serial port registration, but does not involve unauthorized data access or exposure.

Mitigation Strategies

Apply the kernel patch that adds a NULL check for uart->port.dev before calling has_acpi_companion(). Update to a kernel version that includes this fix. If immediate patching is not possible, avoid using legacy non-OF/non-ACPI serial device registrations until the fix is applied.

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