Background.The rapid expansion of open-source software has introduced significant security challenges, particularly concerning supply chain attacks. Software supply chain attacks, such as the NotPetya attack, have underscored the critical need for robust security measures. Managing dependencies and protecting against such attacks have become important, leading to the emergence of Software Bill of Materials (SBOMs) as a crucial tool. SBOMs offer a comprehensive inventory of software components, aiding in identifying vulnerabilities and ensuring software integrity. Objectives. Investigate the information contained within SBOMs in Python and Gorepositories on GitHub. Analyze the evolution of SBOM fields over time to understand how software dependencies change. Examine the impact of the US Executive Order of May 2021 on the quality of SBOMs across software projects. Conduct dynamic vulnerability scans in repositories with SBOMs, focusing on identifying types and trends of vulnerabilities. Methods. The study employs archival research and quasi-experimentation, leveraging data from GitHub repositories. This approach facilitates a comprehensive analysis of SBOM contents, their evolution, and the impact of policy changes and security measures on software vulnerability trends. Results. The study reveals that SBOMs are becoming more complex as projects grow, with Python projects generally having more components than Go projects. Both ecosystems saw reductions in vulnerabilities in later versions. The US Executive Order of 2021 positively impacted SBOM quality, with measures like structural elements and NTIA guidelines showing significant improvements post-intervention. Integrating security scans with SBOMs helped identify a wide range of vulnerabilities. Projects varied in critical vulnerabilities, highlighting the need for tailored security strategies. CVSS scores and CWE IDs provided insights into vulnerability severity and types. Conclusions. The thesis highlights the crucial role of SBOMs in improving software security practices in open-source projects. It shows that policy interventions like the US Executive Order and security scans can significantly enhance SBOM quality, leading to better vulnerability management and detection strategies. The findings contribute to the development of robust dependency management and vulnerability detection methodologies in open-source software projects.