On April 27 Ethan Nunn a Youtuber that goes with the handle of ENunn, tweeted about Cartoon Network co.uk site being hacked.
The Twitter thread shows additional examples of other Cartoon Network domains being compromised.
The company in UK acknowledged the issue and released this information.
Edit 05.02: all tweets have been deleted, so here is the original tweet:
Sudorealistic claims that the hack was intended to show how vulnerable CN is, yet from the timeline there is no indication that the hackers tried to contact the company to fix the vulnerability before the attack.
According to this google doc, it looks like Sudorealistic has a history in downloading, streaming or consuming CN content.
There is also a hint that the Turner Media admin panel may have been used to perform the hack.
I tried to reach out to the Hacker for more clarification, but the request remained answered.