How can I cover my extremely glossy black kitchen cabinets?

Maybe try a paint and primer in one if you want a quick solution. You may need a few coats to cover the black paint. Behr makes a good one

In order for paint to adhere, you will need to degloss and either sand or scuff for the paint to adhere. Also, clean with TSP before primer & paint.

Have you considered contact paper?

How about removing the doors and having open shelves?

Here's a link to a youtube video for step by step instructions - its for painting furniture but the same steps can be used to update your cabinets. https://youtu.be/GsWmjHmA_FA

I am pretty sure there are de glossers out there for what you want. I Believe denatured Alcohol works as a DE glosser but you should ask first. Go to a reputable paint store and ask a lot of questions. You will also want to paint on a primer before painting.

I'm going to vote against painting since you say the cabinets will be replaced in a year anyway. Time flies!

You CAN paint cabinets doing the things others have suggested. And a DIY job done right can look great. But even so, glossy black is going to be hard to cover IMO especially if you want to go to a light color. Even with the necessary primer you'll likely need multiple coats with sufficient dry time between coats. So it will NOT be an especially quick job. And of course you'll need to remove all the doors and hardware first (be sure to label) as the doors will need to be laid flat for painting. It's alot of work IMO if you have an average number of cabinets. And a bad paint job from poor prep, not enough coats, cheaper paint and so on will look bad. I'd consider Kathy's idea about converting some cabinets to open shelving to tamp down all the black as a temporary solution. And just dream of your new cabinets. If you do decide to paint, I'd do as Joanne suggests and consult a reputable paint store for advice. Do take a door with you so they'll know what you are trying to cover.

Another possibility if the cabinets are structurally sound wood and have the features you want is to consider refacing instead of replacement. It is less expensive so maybe you could do that sooner than a year.