Hi there,
Hope you are doing well.
6836 rank in VITEEE is very good.
The previous year cutoffs for VIT Vellore were as follows:-
1) Computer Science and Engineering:- 7,000
2) Computer Science and Engineering( speciality in Bioinformatics) :-13,500
3) Computer Science and Engineering( speciality in Information Security):- 7,500.

Hope it would help.
Thank You.