Yet another dubious claim with regard to Rav Yisroel's familial line was noted just a few hours ago, on his just concluded yahrzeit, on a popular website. However, this time it was not of a descendant, but rather an alleged ancestor. The claim was that R. Yisroel's father, R. Zev Wolf Lipkin, was a descendant of the Vilna Gaon, which would mean that Rav Yisroel was the same.
I felt that something was wrong when I read it, as I didn't recall such a thing from the past.
It seems clear that it is wrong, based on the following -
1) It was not heard in the past. Such a close familial connection between two Lithuanian Torah giants would likely be well known.
2) Rav Yisroel Salanter was born in 1810 למספרם, less than twenty years after the petirah of the Vilna Gaon. His father, Rav Ze'ev Wolf Lipkin, was born twenty some odd years earlier, in 5546, when the Gaon was still alive. The writer writes very vaguely that Rav Zev Wolf was a descendant of the Gaon, without specifying what kind of descendant. Since the Gaon was was in his sixties when Rav Zev Wolf was born, let us assume that they meant a grandson or perhaps great grandson. If that was the case, it would be clearly known and should be stated as such, rather than just the vague claim of being a 'descendant', which sounds like someone who was born many years and generations after, when lines of descent and exact relationships often become unclear with the passage of time and development of different family branches.
3) We do have some information about Rav Yisroel's family and it does not contain such a claim. See for example, in this fine Rabbinic genealogy website from Eretz Yisroel.
One may wonder how such a claim even came into being, if it is totally lacking in basis. It is hard to figure out some things, but perhaps someone saw a statement somewhere that placed Rav Yisroel in a line following the Gaon, and misinterpreted it to mean that he was a physical descendant, when actually what was meant was a kind of spiritual lineage. Hopefully people will be more careful in the future, as this is not the first error I have noted in compilations of yahrzeit information.