Welcome in the forum!
No, it is not accurate enough. I would suggest you to use an x-tal for clock generation. the internal oscillator has @ 3MHz a precision of 1% which is not good enough for CAN specs.
@bob - however if you're using the PLL and USB, the clock accuracy is increased considerably. While my own testing is *far* from thorough, I seem to have no issues with CAN when using USB as well.