I don't think the Soviets would let foreign aid to drop in to their sphere of influence so easily, with the aid, culture and ideals may filter in somehow and violent and stronger revolutions than IOTL could happen.
I am aware, but at this transition period, everyone was still "friends" with each other. The US even offered to help the Soviets, but they refused, and at this point, Poland and Czechoslovakia were both still newly independent, giving them a glimmer of hope to be independent.
Now, Hungary, Romania, Bulgaria, Baltic and whatnot were unlucky enough to be Axis or conquered, so they couldn't accept any aid, but let's say that the Russians don't due anything at first, due to fars from a nuke.
What occurs after that?