CVE-2026-89958

/// Technical description

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

s390/vfio-ap: Fix dereference matrix_mdev->kvm without checking for NULL

The ap_driver structure has two fields which are function pointers to

callbacks:

* .on_config_changed: called at the start of the AP bus scan function to

notify the device driver that the host AP

configuration has changed and the associated AP

devices will be added or removed accordingly. This

gives the implementor a chance to evaluate the

configuration changes and respond to them before

the associated devices are added or removed.

* .on_scan_complete: Called at the end of the AP bus scan function to

notify the device driver that the host AP

configuration has changed and the AP devices have

been added or removed accordingly. This gives the

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References