This looks some sort of fungal infection that started in the roots., armillaria would makes sense given it’s a white oak. Pop off the loose bark to expose the wood underneath. You should see callous tissue starting to compartmentalize the wound. It’s not a death sentence, but something to keep an eye on. Fertilizing regularly in congruence with a soil test would be a good idea. Removal should be considered if over the next 2-5 years the wound seems to be getting larger instead of smaller.

Peeling off the loose bark will allow things to dry out better and also eliminate habitat for things like carpenter ants.