CVE-2026-89795

What it is

In the Linux kernel, the following vulnerability has been resolved: PCI: Allow per function PCI slots to fix slot reset on s390 On s390 systems, which use a machine level hypervisor, PCI devices are always accessed through a form of PCI pass-through which fundamentally operates on a per PCI function granularity. This is also reflected in the s390 PCI hotplug driver which creates hotplug slots for individual PCI functions. Its reset_slot() function, which is a wrapper for zpci_hot_reset_device(), thus also resets individual functions. Currently, the pci_create_slot() assigns the same pci_slot object to multifunction devices. This approach worked fine on s390 systems that only exposed virtual functions as individual PCI domains to the operating system. Since commit 44510d6fa0c0 ("s390/pci: Handling multifunctions") s390 supports exposing the topology of multifunction PCI devices by grouping them in a shared PCI domain. This creates a problem when resetting a function through the hotplug driver's slot_reset() interface. When attempting to reset a function through the hotplug driver, the shared slot assignment causes the wrong function to be reset instead of the intended one. It also leaks memory as we do create a pci_slot object for the function, but don't correctly free it in pci_slot_release(). Add a flag for struct pci_slot to allow per function PCI slots for functions managed through a hypervisor, which exposes individual PCI functions while retaining the topology. Since we can use all 8 bits for slot 'number' (for ARI devices), change slot 'number' u16 to account for special values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-09-16 11:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-30 13:20 UTC Last updatedMost recent change to the record

Details

Published

2026-09-16 11:16 UTC

Last modified

2026-10-30 13:20 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Received

Attack profile CVSS 3.1 · 8.4

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

Availability

High