In the Linux kernel, the following vulnerability has been resolved:

Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet

Make finger2 (and also finger1) unsigned, so that if the finger index in
the packet is 0 then subtracting 1 creates an array index which overflows
above the existing check for FOC_MAX_FINGERS, as the existing comment says
it should, instead of writing to state->fingers[-1].