CVE-2026-89956

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A locking issue exists in the s390/vfio-ap component when accessing the matrix dev->mdev list of ap matrix mdev objects. The vfio ap mdev probe() function and the vfio ap mdev for queue() function (called by status show) fail to hold the matrix dev->guests lock mutex when adding to or traversing the list. Instead, vfio ap mdev probe() incorrectly uses the matrix dev->mdevs lock mutex, which is intended to protect fields within an object rather than the list itself. This concurrency flaw could lead to use-after-free scenarios or kernel memory corruption if objects are created or removed simultaneously.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.