Is this Rustoleum Spray Paint safe for use on bathroom vanity light fixtures?

The can reads it should not be stored over 120 degrees didn't mention anything about once it was applied. I painted a ceiling fan with lights and have had no problems. If you feel uncomfortable about it there is spray paint you can buy for high heat items such as stoves. I have never used it so I can't say how well it works.

We used it on a wood frame we built for around the bathroom mirror and have not had any problems. We did this in a previous bathroom and had no problems with it, as well.

I am using this on light fixtures, once fully cured it should be just fine.

Once fully cure, Rust-Oleum Universal Spray Paint is not flammable, it is ideal for refinishing light fixtures. However, this product is not designed to withstand temperatures of over 200°F and may discolor and crack or peel if applied to surfaces that exceed these temperatures. While most light fixtures do not reach temperatures this high, we recommend testing the surface temperature before application.

This paint should do fine on a bathroom light fixture in my opinion. Don't exceed the wattage specified on the fixture! Better still, switch to LED bulbs to save electricity and reduce heat. For the painting, proper prep work is the key! Take the fixture down so you can get at all the nooks and crannies with the spray. If you haven't used a spray can before, practice a bit first and be aware of overspray. Follow the manufacturer's instructions. In particular make sure it is clean and dry. Use masking tape carefully to protect areas you don't want painted. Be sure the paint is completely dry before you put it in use.