---
id: "CVE-2026-98753"
kind: "vulnerability"
aliases: ["CVE-2026-98753"]
title: "Linux kernel: tty port race lets ioctl reach a powered-down port"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["linux-kernel", "runtime", "self-hosted"]
not_affected_if: []
published_at: "2026-10-18T16:17:29+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:16:54+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98753", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: tty port race lets ioctl reach a powered-down port

A race between a TTY ioctl and a hangup or open can leave a TTY port in a state where I/O is attempted on a port that is gone or powered down. The sources describe the result as possible kernel panic or NULL-pointer dereference, and the fix restores the TTY_IO_ERROR flag when port activation fails.

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

## How to check

- Check the running kernel version with `uname -r` and compare it to the fixed kernel release listed in the advisory, which the sources do not name
- unknown

## Fix

- Update the Linux kernel to a release that includes the tty_port fix for TTY_IO_ERROR on activation failure; the fixed version is unknown from the sources
- unknown

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98753

## From the sources

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

tty: tty_port: restore TTY_IO_ERROR on activation failure

Make sure to restore the TTY_IO_ERROR flag if activation fails to
prevent I/O attempts on a port that is gone or powered down.

This specifically avoids issues like kernel panic due to unclocked
accesses or NULL-pointer dereferences when accessing powered down or
deregistered ports when a TTY ioctl races with hangup and open.

Note that the flag is set again in tty_port_close() but not restoring it
on activation failure leaves a window where drivers fail to handle the
ioctl-hangup race.

---

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