Final answer:
A CPA can disclose confidential information without client consent only if there is a legal requirement, such as a subpoena. Disclosures to voluntary quality control boards, likely successor auditors, or state disciplinary bodies generally require client consent unless legally mandated.
Step-by-step explanation:
A CPA should not disclose confidential client information contained in working papers without the consent of the client. The only exception to this rule is when such disclosure is legally required, such as in response to a valid subpoena from a federal court. Hence, without consent, disclosing information to a voluntary quality control review board, a CPA firm that is a likely successor auditor, or even a disciplinary body created under state statute would not be appropriate unless there is a legal obligation that overrides the confidentiality agreement.