A null pointer dereference occurs in the Linux kernel when restoring memory bandwidth counter state on systems that support the ARM MPAM feature. The bug manifests as a kernel oops and a call trace referencing __ris_msmon_read and mpam_restore_mbwu_state. The failure results in a sudden interruption of kernel operations and, consequently, a denial of service to the affected system. Based on the description, it is inferred that the vulnerability requires local execution or privileged manipulation of kernel state; there is no evidence of a remote attack vector.

The affected systems are Linux kernel installations that include support for ARM Multi‑Policy Adaptive Memory (MPAM). In particular, any kernel version that implements mpam_restore_mbwu_state and __ris_msmon_read without the local val variable patch is vulnerable. The specific kernel releases are not enumerated in the available data, so all unpatched ARM kernel builds should be considered at risk.

The CVSS score is not provided, but the impact is a kernel crash, which can be classified as high severity for availability. The EPSS score is not available and the vulnerability is not listed in CISA's KEV catalog, suggesting limited known exploitation. Attackers would need locality or elevated privileges to force the problematic state transition, making exploitation more difficult. Nevertheless, the risk remains significant for systems that rely on continuous operation, as an unpatched kernel could be forced into a crash through manipulation of memory bandwidth monitoring.