---
id: CVE-2026-58093
title: >-
  The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process
  tree lock
summary: >-
  The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process
  tree lock.  After reacquiring the tty lock, the handler did not revalidate the
  state of the terminal, and could proceed to link a terminal that was
  concurrent…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
  - CWE-416
vendor: freebsd
product: freebsd
affected:
  - freebsd = 14.4
  - freebsd = 15.0
  - freebsd = 15.1
published: '2026-08-26'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T13:25:33.060'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-58093'
references:
  - url: 'https://security.freebsd.org/advisories/FreeBSD-SA-26:62.tty.asc'
    label: secteam@freebsd.org
tags:
  - nvd
epss: 0.00096
epssPercentile: 0.00669
ingestedAt: '2026-09-24T13:43:25.662Z'
---

## Overview

The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process tree lock.  After reacquiring the tty lock, the handler did not revalidate the state of the terminal, and could proceed to link a terminal that was concurrently being destroyed to the calling process' session.

An unprivileged local user can exploit this race condition to escalate privileges.

## Affected

- `freebsd = 14.4`
- `freebsd = 15.0`
- `freebsd = 15.1`

## Remediation

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