According to the RIoTboard user manual and schematic, it's the heavy i.MX6 Solo, which would include FlexCAN. I don't know whether it's available on external pins or whether there's software support.
It's a MCIMX6S5DVM10AB on the board, which is an i.MX6 Solo and it does support CAN (via the FlexCAN module). According to the schematic and RM, while there isn't a direct external pin connection on the board, you could access the signals via some resistors/external interfaces on the board:
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