In today's financial landscape, data lakes have become essential for storing vast amounts of diverse and complex data. However, the security and governance of sensitive financial information within these repositories present significant challenges. Ensuring the protection of this data from breaches and unauthorized access is paramount, given the severe repercussions of potential data leaks. This abstract explores the key security concerns associated with financial data lakes, including issues of data integrity, confidentiality, and compliance with regulatory standards. Additionally, it highlights the importance of robust governance frameworks that encompass policies, procedures, and technologies designed to manage and safeguard data effectively. Solutions such as encryption, access controls, and regular audits are discussed as critical components in mitigating security risks. Moreover, the role of data governance in maintaining data quality, establishing clear accountability, and ensuring compliance with laws like GDPR and CCPA is examined. By addressing these challenges, financial institutions can leverage the full potential of data lakes while maintaining the highest standards of security and governance, thereby fostering trust and reliability in their data management practices.