The Linux kernel mailbox driver for Mitsubishi IPC Subsystem Interface contains a flaw where a failed buffer allocation by devm_kasprintf() is not checked for NULL. If the allocation fails, the driver proceeds to use the NULL pointer, resulting in a null‑pointer dereference that causes the kernel to panic and crash. This crash interrupts normal kernel operation, leading to a local denial of service.

All Linux kernel builds that include the mchp‑ipc‑sbi mailbox driver and contain the unpatched code path. Exact version information is not specified; any kernel older than the commit that added the null check may be affected.

The vulnerability is local and requires an attacker to trigger the function that calls mchp_ipc_get_cluster_aggr_irq(). No EPSS score or CVSS rating is available, and the issue does not appear in the CISA KEV catalog, indicating no publicly known exploits. However, the null‑pointer dereference in kernel space is high severity, and a successful exploit would result in a kernel crash and service disruption.