An unfortunate problem that occurs with roof vents is that they tend to leak. Often this is a result of heavy rainfall or other harsh weather conditions that can wear down these more vulnerable parts of the roof. However if this does occur the leaks can be fixed relatively quickly.
Spotting the leak
The first thing to do is to find exactly which part of the roof vent is leaking. Check for cracked housings on plastic roof vents and broken seams on metal ones. You might be tempted to throw caulk at the problem, but that solution won’t last long. There’s really no fix other than replacing the damaged vents.
Also look out for pulled or missing nails at the base’s bottom edge. If this is the case, replace them with rubber-washered screws. In most cases, you can remove nails under the shingles on both sides of the vent to pull it free. There will be nails across the top of the vent too which you can work those loose without removing shingles.