We don't know, basically. The only safeguards that exist legally are the ones in the Canada Elections Act, which says that the parties cannot use the data Elections Canada provides except for a federal electoral purpose, which is fairly soft criteria. It has nothing to say about the other information, however, and once our information is commingled with other information, it's hard to say whether it's our information or somebody else's.
On September 25th, 2018. See this statement in context.