Disc brakes have been allowed for cyclocross racing by UCI since 2011. And the maximum tire size allowed by UCI for cyclocross racing is 33mm. Used to be 35mm, but it was changed also for 2011 season.
I don't know if the Masi meets the other UCI geometry requirements for CX bikes, but most likely it does. So it would be UCI ok as long as you run proper tires. And, for what is worth, many CX bikes are sold with non-UCI compliant tires. Specially the lower spec models, because most people will not be racing UCI sanctioned races.