Here’s the rule
"A leading horse, if clear, is entitled to any part of the track. If a leading horse or any other horse in a race swerves or is ridden to either side so as to interfere with, intimidate, or impede any other horse or jockey, or to cause the same result, this action shall be deemed a foul. If a jockey strikes another horse or jockey, it is a foul. If in the opinion of the stewards a foul alters the finish of a race, an offending horse may be disqualified by the stewards."

According to Bloodhorse, an appeal might be coming.

How clear was he when he came over looks like the only question now.