Heat damage or something else?

I'm cleaning this cabinet above the range/micro and noticed this mark on the back. I mostly keep cooking oils, vinegars, etc in here. Does this look serious?

Update: well it ain't pretty, but it shouldn't burn the house down. For anyone concerned, my electrician approves. Thank you all for your help today.

https://lemmy.world/pictrs/image/02af7268-bd1d-4192-8a63-ab5014a33835.jpeg