---
id: "CVE-2026-98747"
kind: "vulnerability"
aliases: ["CVE-2026-98747"]
title: "Linux kernel serial core: NULL pointer dereference on serial port unregister"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["kernel", "linux", "other", "serial"]
not_affected_if: []
published_at: "2026-10-18T16:17:28+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:16:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98747", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel serial core: NULL pointer dereference on serial port unregister

In the Linux kernel serial core, unregistering a port with no port device installed dereferences a NULL pointer and crashes the kernel. The sources describe a crash path triggered through unbinding the serial8250 driver, with no stated code execution or data exposure.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98747

## From the sources

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

serial: core: fix NULL pointer dereference in serial_core_unregister_port()

port->port_dev is NULL when no port device is installed: it is cleared
on teardown, and never set if registration failed before
serial_core_port_device_add().  serial_core_unregister_port() passes it
straight to serial_core_get_ctrl_dev(), which dereferences it:

  KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
  RIP: serial_core_unregister_port
  Call Trace:
   serial8250_unregister_port
   serial8250_remove
   unbind_store

Return early when there is no port device, and read port->port_dev
under port_mutex.

Also clear port->port_dev on the serial_core_register_port() error
path, where the port device has already been removed.

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