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 ]
Affected products
linux: linux kernel
References7
- git.kernel.org/stable/c/01e8751b37a366b1ca561add0042f2ceb18c03bf Patch
- git.kernel.org/stable/c/0398b641be2b66c2fc7e0163c606ef19372e7ad5 Patch
- git.kernel.org/stable/c/06724a60cfa9767ea90b0f5d3dfb5cdd251b64f5 Patch
- git.kernel.org/stable/c/29f60d3d06818d40118a30d663231f027ae87a05 Patch
- git.kernel.org/stable/c/ad86ac604f8391c0212a91412d4f764c7a85f254 Patch
- git.kernel.org/stable/c/b803811485ac0b2f774b6bf3abc8b999ba3b7033 Patch
- git.kernel.org/stable/c/f132e089fe89cadc2098991f0a3cb05c3f824ac6 Patch
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 2 · as of 13 November 2026
- CWE
- CWE-476
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.