Micro frontends have become popular in modern web application development due to their scalability, agility, and faster development cycles, but they also introduce security challenges that developers must address. One key issue is inconsistent dependency management, which can lead to version mismatches and potential vulnerabilities, particularly when shared libraries are involved. Another concern is the secure handling of authorization tokens in hybrid mobile apps, where it's recommended to let the native app communicate directly with servers to prevent token access through JavaScript. Additionally, feature isolation is crucial to avoid inter-app communication, and implementing a zero-trust policy with mechanisms like Cross-Origin Resource Sharing (CORS) and Content Security Policy (CSP) headers can enhance security. Despite these challenges, micro frontends can promote security by organizing business logic into independent modules that can be secured individually.