Members of the iPhone Dev Team have dropped hints on Twitter that it will be possible to jailbreak the new Apple TV. Team members pod2g and iphone_dev have both mentioned that the SHAtter exploit has been able to decrypt the Apple TV firmware's keys. While Apple TVs are not yet in people's hands, the firmware is available from Apple's public distribution servers.
Team Member MuscleNerd also warned potential jailbreakers via Twitter: "Those interested in *potential* AppleTV JBs, better buy early! Remember iPhone 3GS hardware was updated to fix JB hole." Indeed, Apple has already released a firmware update for the Apple TV, though we don't know if it addresses this exploit.