Wikitree has
https://www.wikitree.com/wiki/Stewart-33235 which says that Catherine was the daughter of Donald Stewart and Elizabeth Cumming, and gives as its source "
Bezansons from Nova Scotia", by Dorothy Evans, Halifax, Nova Scotia: Privately Published, 1986, revised 1991 (bezansons.com)
So it looks as if the parentage of Catherine is from this (secondary) source. You need to get hold of a copy of the book and see what the author's source is for saying that these were her parents.
However this is linked to another version saying she was born in Glasgow and that her father was born in Strathdon in 1778.
This version says that Donald Stewart, born 1778, husband of Elizabeth Cumming, was the son of Arthur Stewart and Beatrix Farquharson, and that he died in 1862. The son of Arthur Stewart and Betty Farquharson did indeed die in 1862 - on 26 April in Tornahaish, Strathdon. However his death certificate says he was married to Janet Downie - and as the informant was his son Arthur, one assumes that Arthur knew better who his own mother was than some careless researcher a century and a half after the event.
The 1861 census shows at Tornahaish, Strathdon, Donald Stewart, 83; wife Janet, 81; daughter Euphemia, 50 and son Arthur, 48, all born in Strathdon. So Euphemia would have been born in 1810/11 and Arthur in 1812/13, contemporary with the recorded children of Donald Stewart and Elizabeth Cumming.