Is this a new issue? Have you changed string type? Is this a "new to you" guitar? Is the buzz still present if you play a little less strongly?
Quite possibly a slanted saddle would solve the problem: the bone being a little higher on the bass side.
If you want to try it yourself, you can make a brief test by putting a tiny sliver of paper (or two ) or very thin card, or wood veneer if you have some, underneath the saddle. If this stops the buzzing, then you know how much extra height is needed. Then buy a bone blank or two (quite cheap on the auction site) and use sandpaper to get it to a slightly slanted shape with the bass side a little bit higher than the original but the treble sides the same. A plastic saddle would be much easier to shape if you just want to do a test before spending time doing a bone saddle.