See if you see the notifications for vacancies in ISRO by visiting the ISRO careers section then you will observe the fields are exactly mentioned i.e., if the vacancies for CSE then its mentioned for CSE only. Now in general if you see the trends then the vacancies for CSE is 1-5 every year i.e., much less than that of EE or ECE or ME. SO you can go with your field to ISRO and you have better scopes. Now if you want to go for CSE then I would say its dependent on the notification. If it says the stream then you will eligible.

I hope my answer helps. All the very best for your future endeavors!