2006 Pontiac G6 - brake lights turn on when brakes aren't pressed

The brake lights will turn on when the brakes aren’t pressed, but once I press them in far enough (not very far) they turn off, then once I press the brakes hard enough to the point where I’m actually slowing down, they turn back on.

Cruise control doesn’t work while the lights are on and the brakes aren’t pressed. If I have the brake pedal in the “dead zone” where the lights are off, then turn on cruise control, then let go of the brakes, a few seconds later, the brake lights will turn back on and cruise control will turn back off.

This problem will sometimes fix itself for days at a time, or maybe for just one drive, but then comes back.

I haven’t been able to find anything about this particular problem, but I’ve seen that when brake lights stay on, it’s probably the brake light switch, or the wiring connected to it, or maybe even a fuse. I’m thinking it’s the switch though, given that the lights turn on and off depending on the position of the pedal.

What could be causing this problem?