The legal responsibility of e-commerce platforms in the disclosure of customers' commercial data is one of the most significant challenges in the fields of cyber law and commercial law in the era of information technology. This article aims to examine the legal foundations of civil liability of e-commerce platforms regarding the protection of users' commercial data and to analyze the gaps and shortcomings of the current laws. The main research question is how the existing legal systems can determine the legal responsibility of these platforms in disclosing commercial data and provide appropriate enforcement guarantees. The necessity of this research arises from the significant increase in the use of e-commerce platforms and the growth of new technologies, which have caused numerous legal issues in the field of protecting sensitive data, accompanied by legal gaps and lack of specific regulations. The research method in this article is descriptive-analytical and comparative, conducted through documentary study and review of domestic and international laws, legal doctrines, and relevant judicial precedents. The findings indicate that existing laws in Iran lack comprehensive definitions and sufficient enforcement guarantees to protect commercial data on e-commerce platforms, which has increased the vulnerability of users’ rights and decreased public trust in these technologies. Moreover, by comparing different legal systems, solutions for legal reform and drafting specific regulations for smart contracts and civil liability in this field are proposed. The innovation of this study lies in the analytical combination of cyber law and commercial law topics and the provision of a coherent framework for the legal responsibility of platforms in disclosing commercial data, which can pave the way for new legal policymaking.