Corporations Code § 12477
ARTICLE 2. Additional Provisions Relating to Election of Directors
An action challenging the validity of any election, appointment or removal of a director or directors must be commenced within nine months after the election, appointment or removal. If no such action is commenced, in the absence of fraud, any election, appointment or removal of a director is conclusively presumed valid nine months thereafter if the only defect in the election, appointment or removal is the failure to give notice as provided in this part or in the corporation’s articles or bylaws.