True, the CBC is anti-gun. However, the 67% seems to be accurate, the article just isn't clear about where it came from. While the article makes it seem like the study compared bear spray to guns, it was actually the study's author (or at least his University) who appears to have drawn the line between the study you linked to and his previous work.

The following is from the University's press release:

"... Smith and colleagues analyzed 20 years of bear spray incidents in Alaska, home to 150,000 bears. He found that the spray effectively halted aggressive bear behavior in 92 percent of the cases ... Smith's previous research found that guns were effective about 67 percent of the time."

The CBC article did not make it clear that the 67% figure came from a previous study, not from the bear spray study.

It seems that similar numbers are quoted by other researchers. The U.S. Fish and Wildlife Service have a fact sheet Bear Spray vs. Bullets which says:

"Law enforcement agents for the U.S. Fish and Wildlife Service have experience that supports this reality -- based on their investigations of human-bear encounters since 1992, persons encountering grizzlies and defending themselves with firearms suffer injury about 50% of the time. During the same period, persons defending themselves with pepper spray escaped injury most of the time, and those that were injured experienced shorter duration attacks and less severe injuries. Canadian bear biologist Dr. Stephen Herrero reached similar conclusions based on his own research -- a person’s chance of incurring serious injury from a charging grizzly doubles when bullets are fired versus when bear spray is used."

I have nothing vested in these results, but everything I find seems to indicate that bear spray is more effective than firearms as a general rule.