CVE-2023-53746

In the s390 VFIO-AP driver, memory allocated for the vfio_matrix_dev structure is never released during device cleanup. The release callback incorrectly uses dev_get_drvdata() to locate the object, but since it was never stored there, the function returns NULL and kfree() silently accepts it. The correct approach requires container_of() to retrieve the enclosing structure.

This leak occurs exclusively on IBM s390 mainframe systems using VFIO passthrough for cryptographic adapters. Systems not utilizing AP device virtualization remain unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.