No, Royal Challengers Bangalore (RCB) has not won the Champions League Twenty20 (CLT20).
While RCB has had several strong performances in various tournaments, they haven't secured the CLT20 title. According to the provided reference:
The team also finished runners-up in the 2011 CLT20, losing the final against the Mumbai Indians.
This indicates that their best performance in the CLT20 was finishing as runners-up in 2011. They lost to the Mumbai Indians in the final. RCB has also made three final appearances in the IPL, losing all of them. This reinforces the fact that while they've been competitive, they haven't clinched major titles, including the CLT20.
