Power supply cable too short?

Good morning,

I recently upgraded my PC components. The only things I kept from my previous PC were the power supply and graphics card. While I was assembling my PC, I noticed that one of the power supply cables to the motherboard was too short.

The cable is an 8-pin connector and needs to go in there. Currently, I have a workaround where the power supply is outside the case, but I don't want to keep it that way. So I'm wondering what would be the best approach. I don't want to buy a new power supply. I've heard that there are 8-pin extenders. Does that apply here?

Thank you