Stuck parking brake

So I went to bonnabel boat launch today to take a very brief boat ride and to shake down a few things that I did some work on. After all systems were a go I brought her back in and tied the boat up and grabbed my truck to back her down. Got the boat on and go to pull out and back drivers side wheel is just spinning. I figured I might have backed down passed the ramp and the truck didn't have enough traction so I pulled the boat off but same thing. Then I knew it was the parking brake. Ended up having to have someone hook up to my tow strap and drag me. Worked on t a few minutes and after pumping the brakes hard I heard it pop free and all was back to normal.

With all that said what do y'all think is actually wrong and how bad of a fix is it. I'm leaning very heavily to corroded cable by idk