During December 2025, Jing Guo focused on security hardening for the percona/percona-server-mongodb repository by removing insecure user data serialization logic. Jing refactored the backend C++ code to eliminate the User::reportForUsersInfo function, which previously generated BSON representations of sensitive user information, including credentials and roles. This change reduced the risk of credential leakage and aligned with data minimization and compliance requirements. Jing’s approach emphasized audit-friendly change management by linking the update to a specific commit and issue for traceability. The work demonstrated strong backend development skills in C++ and careful handling of BSON serialization to improve codebase security.