Array index error in the MidiManagerUsb::DispatchSendMidiData function in media/midi/midi_manager_usb.cc in Google Chrome before 41.0.2272.76 allows remote attackers to cause a denial of service or possibly have unspecified other impact by leveraging renderer access to provide an invalid port index that triggers an out-of-bounds write operation, a different vulnerability than CVE-2015-1212.