---
id: CVE-2026-58094
title: >-
  The FIOSSHMLPGCNF ioctl(2) operation configures the page size for a largepage
  shared memory object
summary: >-
  The FIOSSHMLPGCNF ioctl(2) operation configures the page size for a largepage
  shared memory object.  This is intended to be used immediately after creating
  the object, before any memory is allocated for the object.  The handler
  checked w…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-367
vendor: freebsd
product: freebsd
affected:
  - freebsd = 14.4
  - freebsd = 15.0
  - freebsd = 15.1
published: '2026-08-26'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T13:17:24.210'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-58094'
references:
  - url: 'https://security.freebsd.org/advisories/FreeBSD-SA-26:63.posixshm.asc'
    label: secteam@freebsd.org
tags:
  - nvd
epss: 0.00119
epssPercentile: 0.01557
ingestedAt: '2026-09-24T13:43:25.662Z'
---

## Overview

The FIOSSHMLPGCNF ioctl(2) operation configures the page size for a largepage shared memory object.  This is intended to be used immediately after creating the object, before any memory is allocated for the object.  The handler checked whether a page size had already been configured without holding the rangelock.  Two concurrent callers could both observe an unconfigured object and set conflicting page sizes, leaving the object in an inconsistent state.

An unprivileged local user can exploit this race 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.