Worked on security hardening for the lmnr-ai/lmnr repository, focusing on protecting sensitive routes and reducing risk exposure. Addressed a critical vulnerability by upgrading Next.js to version 15.2.3, directly mitigating CVE-2025-29927 and preventing potential middleware bypasses. The solution involved validating the x-middleware-subrequest header and enforcing stricter access controls, ensuring unauthorized requests could not reach protected endpoints. All changes were implemented in JavaScript using Next.js and Node.js, with a single, traceable commit for accountability. No new features were released during this period, as the primary goal was to stabilize and strengthen the existing security posture of the application.