Regression testing is a quality assurance process used in cybersecurity and software development to ensure that recent changes, such as updates, patches, or enhancements, have not negatively impacted existing system functionality. By re-running previously completed test cases, regression testing helps identify unintended side effects or new vulnerabilities introduced by the changes. It is crucial for maintaining system stability and security, especially in environments where frequent updates are necessary. Automated regression tests are often employed to increase efficiency and coverage, making it easier to detect issues early and reduce the risk of security breaches or operational failures.