Why is it important to verify whether a CSP violation was enforced or only in report-only mode?

Understanding whether a Content Security Policy (CSP) violation was enforced or only reported is crucial in determining the effectiveness of the security measures put in place. When a CSP is enforced, any violation results in the browser blocking the resource that triggered the violation, thereby actively mitigating potential security threats such as cross-site scripting (XSS) attacks or data injection attacks.

If violations are merely in report-only mode, it indicates that the policy is not preventing any potential threats but is only logging them for analysis without taking corrective action. This distinction allows security teams to assess whether their CSP is functioning as intended and effectively protecting the application from actual threats.

In summary, verifying the enforcement status of a CSP violation helps in understanding if the security risks have been adequately addressed, enabling proactive measures to strengthen the application's security posture.