I don't know the process they used for this, but this chart has CBC leaning to the middle-left (not extreme left), while being highly factual.
It looks like they lean about as far left as the Calgary Herald does to the right (although both are considered highly factual).
From the Association of Media Literacy. I don't really know the source personally, so I can't vouch for it.
https://aml.ca/the-bias-in-media-bias-charts/