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 ]

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-43313
• https://git.kernel.org/stable/c/01e8751b37a366b1ca561add0042f2ceb18c03bf
• https://git.kernel.org/stable/c/0398b641be2b66c2fc7e0163c606ef19372e7ad5
• https://git.kernel.org/stable/c/06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5
• https://git.kernel.org/stable/c/29f60d3d06818d40118a30d663231f027ae87a05
• https://git.kernel.org/stable/c/ad86ac604f8391c0212a91412d4f764c7a85f254
• https://git.kernel.org/stable/c/b803811485ac0b2f774b6bf3abc8b999ba3b7033
• https://git.kernel.org/stable/c/f132e089fe89cadc2098991f0a3cb05c3f824ac6