Ref. No. 1053 Alif
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
Doing masah on socks made of leather is permissible. But to do masah on socks made out of leather there are few conditions to be met. i.e. The Socks must be so thick that water cannot be strained through them, they stay upright because of their thickness, and the person can walk with it about 3 miles. If the socks fulfill all those conditions then it is permissible to do Masah on them. Otherwise it will not. So, in the past, if you did mahas on common socks and performed Salah, then you have to offer those salah again as they were performed without valid wuzu. (and Allah knows best)
Darul Ifta
Darul Uloom Waqf Deoband