共同共有人擅自处分共有房产,其他共有人诉请确认处分行为无效并返还房屋.
案情简述：原被告共同共有一套房产，被告未经原告同意擅自将房屋出售给第三人，原告起诉要求确认房屋买卖合同无效。
Brief of the Case: The plaintiff and the defendant jointly own a real estate. The defendant arbitrarily sold the house to a third party without the plaintiff's consent. The plaintiff sued to confirm the invalidity of the house sales contract.
诉求精准锁死：请求确认被告与第三人签订的房屋买卖合同无效，判令返还房屋并恢复登记原状。
The claim is accurately locked: Request to confirm the invalidity of the house sales contract signed by the defendant and the third party, and order the return of the house and restoration of the original registration status.
法律依据卡死：《中华人民共和国民法典》规定，处分共同共有的不动产，应当经全体共同共有人同意，未经同意擅自处分的，一般认定无效。
Legal basis is firmly established: The Civil Code of the People's Republic of China stipulates that the disposal of jointly owned real estate shall be agreed by all joint owners. Unauthorized disposal without consent shall generally be deemed invalid.
事实证据焊死：不动产权属证明、共有关系证明、房屋买卖合同、未经同意的沟通记录。
Facts and evidence are solid: Real estate ownership certificate, proof of joint ownership, house sales contract, communication record of unauthorized disposal.
对方抗辩理由：
第三人系善意购买且已过户，应善意取得房屋所有权。
被告有权代表全体共有人处分房产。
我方堵死理由：
共有房产未经全体共有人同意，第三人不构成善意取得。
被告无单独处分权，擅自处分行为侵害其他共有人合法权益。
Defenses of the other party:
The third party is a bona fide purchaser and has completed the transfer, and shall acquire the house ownership in good faith.
The defendant has the right to dispose of the real estate on behalf of all co-owners.
Our refutation reasons:
The jointly owned real estate has not been agreed by all co-owners, and the third party does not constitute bona fide acquisition.
The defendant has no right of separate disposal, and the unauthorized disposal act infringes on the legitimate rights and interests of other co-owners.
逻辑闭环推导：被告擅自处分共同共有房产，违反法律强制性规定，房屋买卖合同无效，房屋应予返还。
Logical closed-loop deduction: The defendant arbitrarily disposes of the jointly owned real estate, violating the mandatory legal provisions, the house sales contract is invalid, and the house shall be returned.
