CVE-2026-46022

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> misc: ibmasm: fix OOB MMIO read in ibmasm_handle_mouse_interrupt()<br /> <br /> ibmasm_handle_mouse_interrupt() performs an out-of-bounds MMIO read<br /> when the queue reader or writer index from hardware exceeds<br /> REMOTE_QUEUE_SIZE (60).<br /> <br /> A compromised service processor can trigger this by writing an<br /> out-of-range value to the reader or writer MMIO register before<br /> asserting an interrupt. Since writer is re-read from hardware on<br /> every loop iteration, it can also be set to an out-of-range value<br /> after the loop has already started.<br /> <br /> The root cause is that get_queue_reader() and get_queue_writer() return<br /> raw readl() values that are passed directly into get_queue_entry(),<br /> which computes:<br /> <br /> queue_begin + reader * sizeof(struct remote_input)<br /> <br /> with no bounds check. This unchecked MMIO address is then passed to<br /> memcpy_fromio(), reading 8 bytes from unintended device registers.<br /> For sufficiently large values the address falls outside the PCI BAR<br /> mapping entirely, triggering a machine check exception.<br /> <br /> Fix by checking both indices against REMOTE_QUEUE_SIZE at the top of<br /> the loop body, before any call to get_queue_entry(). On an out-of-range<br /> value, reset the reader register to 0 via set_queue_reader() before<br /> breaking, so that normal queue operation can resume if the corrupted<br /> hardware state is transient.