Cooking corned beef in the oven takes around 4 hours.
To cook corned beef in the oven pour around 8 cups of water around the corned beef in the pan and then cover the corned beef with foil and cook the corned beef on the middle rack in the oven at 324 F for approximately 4 hours which should be good enough.
Corned beef can still show a little pink but yet still be cooked fully so don't be afraid of a little pink in the corned beef as it's perfectly safe.
As long as the corned beef has been in the oven cooking for at least 4 hours it will be done enough to eat even with the pink color.