---
id: CVE-2026-90315
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers

  Currently, the legacy I/O and memory sysfs handlers do not check
  security_locked_down(LOCKDOWN_PCI_ACC…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers

  Currently, the legacy I/O and memory sysfs handlers do not check
  security_locked_down(LOCKDOWN_PCI_ACC…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= eb627e17727ebeede70697ae1798688b0d328b54 <
    cd07aef510ac6a2873e01f9ddddc5492490b0067
  - >-
    Linux >= eb627e17727ebeede70697ae1798688b0d328b54 <
    747b9bbbbdfdee51aee2456388f9b94b5086de4d
  - Linux 5.4
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:17:29.340'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90315'
references:
  - url: 'https://git.kernel.org/stable/c/747b9bbbbdfdee51aee2456388f9b94b5086de4d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cd07aef510ac6a2873e01f9ddddc5492490b0067'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.825Z'
epss: 0.00198
epssPercentile: 0.08448
---

## Overview

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

PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers

Currently, the legacy I/O and memory sysfs handlers do not check
security_locked_down(LOCKDOWN_PCI_ACCESS), leaving the legacy_io and
legacy_mem files unprotected when the kernel is locked down.

Commit eb627e17727e ("PCI: Lock down BAR access when the kernel is locked
down") added the check to pci_write_config(), pci_mmap_resource(), and
pci_write_resource_io() to prevent userspace from programming DMA-capable
hardware that could be used to modify kernel code, but did not cover the
legacy handlers.

As a result, root can still write arbitrary I/O ports and map the legacy
I/O and memory spaces while the kernel is locked down, which is the same
capability the lockdown is meant to remove.

Add the same check to pci_write_legacy_io(), pci_mmap_legacy_mem(), and
pci_mmap_legacy_io().

These generic handlers cover both architectures that define HAVE_PCI_LEGACY
(such as Alpha and PowerPC).

[bhelgaas: add Link]

## Remediation

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