Easy fix. But, first evaluate the likelihood of falling off a ladder and consequences to your wage earning ability when you do fall.

Likelihood is pretty high for guys over 40

This is likely a rain collar issue. Its either not there, or the caulking has failed. Light showing isn't a bad thing depending on where exactly it is peeking through. It's a bit hard to tell from my phone. This is a gas vent and typically consists of several pieces including your flue, the conical flashing, rain collar, and finally the cap itself. The flue is 'loose' in the flashing, that is fine, but the rain cap must be caulked and sealed like a little umbrella.

Blue arrow is where these leaks typically show up based on the water streaks on your flue if it's not caulked..

A roofer came out today and it's that exact spot that failed. He "caulked the **** out of it."