Pic ClickyFirst off- Welcome!
That caulking around that vent really looks gone. I'd for sure be replacing it.
Is that the seem where the roof meets the sidewall? In both cases it would appear that both of these areas could allow water in and cause you damage.
I'm still a noob but both of those look to be needing some tlc. I wish I knew for sure what type of roof you have. You may only need to go over that vent caulking with a wider seem of self leveling sealant. But - to my eye - those cracks look large and inviting places for water to get in, freeze in winter, and work its way into the structure.
