The proper repair is to replace the damaged shingle and anchor (nail) under a undamaged shingle. Shingles have a warrantee of ~15 years when installed like this. Silicon or tar daubs do not have any warrantee, and probably last 1-3 years.

In your case, I think that you may want to buy some spare shingles and take one and cut it to be able to be anchored under the undamaged shingles above the vent and cover the vent pipe nails while having room for the vent pipe. Sorry I can't be more help without pictures.

Edit: I went on a tangent below:

There are a couple spots (like when the roof starts from a wall) where there should be undamaged flashing from the wall that covers the first set of nails.

A quick and dirty trick is to cover the shiner with black silicon and then sprinkle the shingle grit that collects in the gutters on the silicon (so it doesn't decay in the sun, and the repair looks like the rest of the roof).

A less quick and dirtier, but longer lasting fix is to get some roofer fabric and roofer cement, and anchor the fabric under an undamaged single then spread the cement below and above the fabric. It doesn't look great but it will stop leaks from much larger roof cracks (damaged nail base) for a couple years.

Source: YouTube and buying a brand new build house with a bunch of cracked clear silicon repairs to shiners within the first 2 years.