---
id: CVE-2026-43313
title: 'ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()

  In acpi_processor_errata_piix4(), the pointer dev is first assigned an IDE
  device and th…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    ad86ac604f8391c0212a91412d4f764c7a85f254
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    01e8751b37a366b1ca561add0042f2ceb18c03bf
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    b803811485ac0b2f774b6bf3abc8b999ba3b7033
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    29f60d3d06818d40118a30d663231f027ae87a05
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    0398b641be2b66c2fc7e0163c606ef19372e7ad5
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    f132e089fe89cadc2098991f0a3cb05c3f824ac6
  - Linux 2.6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T15:35:12.753548Z'
published: '2026-05-08'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T15:42:48.040Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43313'
references:
  - url: 'https://git.kernel.org/stable/c/06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5'
  - url: 'https://git.kernel.org/stable/c/ad86ac604f8391c0212a91412d4f764c7a85f254'
  - url: 'https://git.kernel.org/stable/c/01e8751b37a366b1ca561add0042f2ceb18c03bf'
  - url: 'https://git.kernel.org/stable/c/b803811485ac0b2f774b6bf3abc8b999ba3b7033'
  - url: 'https://git.kernel.org/stable/c/29f60d3d06818d40118a30d663231f027ae87a05'
  - url: 'https://git.kernel.org/stable/c/0398b641be2b66c2fc7e0163c606ef19372e7ad5'
  - url: 'https://git.kernel.org/stable/c/f132e089fe89cadc2098991f0a3cb05c3f824ac6'
tags:
  - cve.org
epss: 0.00123
epssPercentile: 0.02038
ingestedAt: '2026-11-06T15:54:03.942Z'
---

## Overview

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

ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()

In acpi_processor_errata_piix4(), the pointer dev is first assigned an IDE
device and then reassigned an ISA device:

  dev = pci_get_subsys(..., PCI_DEVICE_ID_INTEL_82371AB, ...);
  dev = pci_get_subsys(..., PCI_DEVICE_ID_INTEL_82371AB_0, ...);

If the first lookup succeeds but the second fails, dev becomes NULL. This
leads to a potential null-pointer dereference when dev_dbg() is called:

  if (errata.piix4.bmisx)
    dev_dbg(&dev->dev, ...);

To prevent this, use two temporary pointers and retrieve each device
independently, avoiding overwriting dev with a possible NULL value.

[ rjw: Subject adjustment, added an empty code line ]

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ad86ac604f8391c0212a91412d4f764c7a85f254`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 01e8751b37a366b1ca561add0042f2ceb18c03bf`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b803811485ac0b2f774b6bf3abc8b999ba3b7033`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 29f60d3d06818d40118a30d663231f027ae87a05`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0398b641be2b66c2fc7e0163c606ef19372e7ad5`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f132e089fe89cadc2098991f0a3cb05c3f824ac6`
- `Linux 2.6.12`

## Remediation

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