From the Snopes article.
“Among the ways these accusations stray from the facts is in attributing a power of veto or approval to Secretary Clinton that she simply did not have. Clinton was one of nine cabinet members and department heads that sit on the CFIUS, and the secretary of the treasury is its chairperson. CFIUS members are collectively charged with evaluating the transaction for potential national security issues, then turning their findings over to the president. By law, the committee can’t veto a transaction; only the president can. According to The New York Times, Clinton may not have even directly participated in the Uranium One decision. Then-Assistant Secretary of State Jose Fernandez, whose job it was to represent the State Dept. on CFIUS, said Clinton herself “never intervened” in committee matters.”