Travis Kalanick, the former Uber chief executive who was ousted in June, is being sued by one of the company's biggest investors.
Benchmark Capital, which owns 13% of the ride-sharing firm, has accused Kalanick of fraudulently attempting to fill board seats with loyal allies.
They said that Kalanick was paving the way for his potential return as chief executive.
A spokesman for Kalanick called the lawsuit "completely without merit".