Hi. i am a cornet player, and i recently wanted to buy a mute for my cornet, but i dont seem to find any specific cornet mute. I wonder if a mute that fits into a trumet can be used for a cornet 2, or do these instruments use different shape mutes? Please answer, i ve looked around and cant find an answer!

I use the same mutes for both my trumpet and my cornet.

Yes, they are the same diameter at the top and the same in length size.
The copper based mutes give the best sound for the trumpet as it become overall more 'raspey'