From: https://github.com/linklayer/cantact-hw

Also: https://wiki.linklayer.com/index.php/CANtact

The CANtact device is a single channel USB CAN interface. It can be used to connect to CAN bus 
systems, including cars, heavy duty vehicles, and industrial automation systems. CANtact works 
on Linux, OS X, and Windows.

From: https://www.tindie.com/products/protofusion/canable-usb-to-can-bus-adapter/

Second usb to canbus opensource