It will be interesting to see the moral gymnastics involved here, seeing as Trump and Corbyn are perceived as being on opposite ends of the political spectrum, and President Trump basically did similar things (take advantage of leaks from Russian agents). I imagine many of the same people that excoriate Trump for this will find a way for Jeremy Corbyn to be innocent, and those that condemn Corbyn will have justified Trump.
The Russians meanwhile, probably just want everyone divided and easy to manipulate. Which has been working pretty well I guess.