The vantage6 technology enables to manage and deploy privacy enhancing technologies like Federated Learning (FL) and Multi-Party Computation (MPC). It is possible to find out usernames from the response time of login requests. This could aid attackers in credential attacks. Version 4.2.0 patches this vulnerability.
https://github.com/vantage6/vantage6/security/advisories/GHSA-45gq-q4xh-cp53
https://github.com/vantage6/vantage6/commit/389f416c445da4f2438c72f34c3b1084485c4e30