---
id: "CVE-2026-98752"
kind: "vulnerability"
aliases: ["CVE-2026-98752"]
title: "Linux kernel: tty hangup race can cause use-after-free and NULL dereference"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["drivers", "linux-kernel", "runtime", "tty"]
not_affected_if: []
published_at: "2026-10-18T16:17:28+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:16:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98752", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: tty hangup race can cause use-after-free and NULL dereference

A race in the Linux kernel's tty port hangup path can let tty_port_tty_vhangup() return before the port is shut down. That can lead to use-after-free and NULL pointer dereferences in racing ioctls or asynchronous hangups.

_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-2026-98752

## From the sources

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

tty: port: fix tty_port_tty_vhangup() race

Drivers rely on tty_port_tty_vhangup() to synchronously hang up their
ports before tearing down resources as part of deregistration (e.g. on
physical disconnect).

If tty_port_tty_vhangup() races with another hangup it may however
return before the port has been shut down. This is in turn can lead to
use-after-free and NULL-pointer dereferences in racing ioctls (including
a synchronous hangup) and in processing of racing asynchronous hangups
(carrier loss).

Add the missing serialisation to tty_port_tty_vhangup() and
tty_port_hangup() so that the former does not return until the port has
been shut down also when there is a racing hangup.

Note that serial core does not use tty_port_hangup(), but it already
holds the port mutex when clearing port->tty and shutting down the port
in uart_hangup().

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_