The mount for the mirror is glued to the glass, then the mirror attaches by fitting the mirror base over the mount, then rotating the base 90 degrees. There are clips in the base that hold on to tabs on the mount, but it is by spring pressure only - you could try bending the clips in the base slightly to tighten their 'grip' and re-mounting the mirror. Here are some pics of what it looks like:

https://www.crossfireforum.org/forum...s-anymore.html

This only will help if the mirror is loose at the base - if it is loose at the adjustment swivel, I don't remember seeing any way of tightening that part up.

Hope this helps...