which specialization in m.sc is good for both isro and software engineer
See this is a very abstract kind of a question. And I think there are no such career MSc courses that are equally applied for both the courses. Now if you want to correlate these two fields then I would say that a MSc in Electronics have a lot of recruitments in ISRO and in IT sectors MSc Electronics are taken as they have good coding skills but in IT's they are paid less as compared to BTech CSE/IT. Thus if you want to go for IT then I would recommend you to go for MCA rather than MSc but if you have genuine interest in ISRO then MSC Electronics can be a great choice for you.
I hope this answer helps. All the very best for your future endeavors!