If it’s definitely the woofer/passive radiator that’s visible on the back, then there’s special speaker glue that is rubberized and extremely sticky. It’s usually black or sort of a natural rubber color. It’s pretty easy to find on Amazon, search speaker glue. Just make sure to follow instructions regarding cure time as if play music through the speaker before it’s cured it’ll just re-rip. Usually 24 hours is a safe cure time.
If you’re going to use an adhesive to repair a tear on the speaker’s outer jacket I’d suggest using Silicone adhesive since the jacket itself is also silicone. It’s usually best, when not concerned with structural strength, to patch or rejoin materials using the same material as the original. This isn’t necessarily the case if the patch, joint, whatever needs to perform as structural body which would take a weight or pressure load, but that depends on the material. I’m not sure if there is a vulcanizing silicone but if there’s a choice between vulcanizing and non-vulcanizing, pick vulcanizing. It’ll fuse the two parts of the jacket back to one another better. If that’s not available to you, vulcanizing rubber cement will work, but will only truly vulcanize rubber materials to rubber materials, not to metal, plastic or wood etc. For sealing the front and rear grill and frame back on, any rubberized adhesive will work. Since it’ll be held together with screws you won’t have to worry about the strength of the adhesive to hold it together as it’s only for sealing the speaker as well as dampening /muting any vibrations between joined parts of the speaker.
Is the torn rubber still in one piece, or not? (Hypothetically, of course, since your actual tear is the woofer, not the jacket) Was it a tear, a puncture or was a piece completely severed off the main portion? If the problem involves a severed piece and you can stomach the possible ugly look, I would consider simply leaving the severed piece out of the equation and just make sure you take care to put the rubberize adhesive along any part that is exposed to another adjacent, separate piece of hard material that will end up giving vibrations once joined. Let there always be something rubber between any two hard metal or plastic pieces so they don’t actually ever touch even when screwed together.
I hope I explained myself well, but If you are confused by what I’ve suggested feel free to ask for more clear instructions in a message. I’ll be making a guide soon for the same speaker, if you still need help, though I’m not planning a full tear down, perhaps it might give some insight. Good luck. Edit: the tear down was completed but this site and my device don’t seem to like each other very much as I’m having trouble posting pictures. Sorry.