Abhishek Bhardwaj upgraded the authentication stack in the apache/druid repository by implementing pac4j version 5.7.3, focusing on enhancing security and stability. He managed dependency updates and license alignments to ensure compatibility with the new authentication extension, while also addressing multiple CVEs and dependency vulnerabilities. His work involved close coordination with security teams, comprehensive code reviews, and targeted CI validation to maintain deployment reliability. Utilizing Java and YAML, Abhishek applied his expertise in authentication, dependency management, and security remediation to deliver a robust solution that improved the project’s security posture without disrupting existing workflows or compatibility for users.