Apple’s statement about the recent increase of iCloud calendar spam to Rene Ritchie:
We are sorry that some of our users are receiving spam calendar invitations. We are actively working to address this issue by identifying and blocking suspicious senders and spam in the invites being sent.
Not sure “identifying and blocking suspicious senders and spam in the invites” is enough to get rid of this problem. The whole idea of being able to freely send calendar invites to anyone with an email address – or abuse Apples iCloud Photo Sharing – is frightening. I’m actually surprised it took the spammers this long to finally find this opening.