Brazilian full-back Fabio has joined on a permanent basis for an undisclosed free.
"I'm very excited to be part of this and I'm looking forward to helping Cardiff. I was at Old Trafford on Tuesday – supporting Cardiff but hoping that my brother did well too, of course," he told the club's official website. "I know this is the right move for me. I spoke a lot to the Manager about coming in and I know that I can help us move up the division."
Meanwhile, winger Zaha has agreed a loan deal until the end of the ongoing Premier League campaign.