This has been rumored and reported for a while, but this report from a Mexican news source seems solid:
Benedict personally tells Legion of Christ to ditch “private vows.”

Pope Benedict XVI had personally asked for the repeal of the private vows professed by the seminarians and priests of the Legionaries of Christ. These were oaths, related to the internal life of the order, which assured its secrecy and impermeability: the first [oath of “charity”] prevented any kind of criticism of superiors and their decisions by members, while the second [oath of “humility”] forbade the religious men from aspiring to positions within it.