How do I fix: The response has no Content-Security-Policy header.?

Start with a report-only CSP, inventory third-party scripts, then enforce a tested policy. Add Content-Security-Policy at Nginx/CDN/server level and monitor violations before strict enforcement.

Will Themerella confirm the How to Fix a Missing CSP Header fix?

Re-run the URL scan after deploying the change. The report re-checks the related signals and updates the issue list and Themerella Score.

Fix Missing Content-Security-Policy Header

Recommended fix

Start with a report-only CSP, inventory third-party scripts, then enforce a tested policy.

This guide is designed to pair with a scanner report. Run a URL scan first, then follow the implementation steps.

Developer task

Add Content-Security-Policy at Nginx/CDN/server level and monitor violations before strict enforcement.

Implementation steps

How to apply this fix

Inventory every script, style, font, image, and connect origin the site loads.
Deploy Content-Security-Policy-Report-Only with a draft policy and a report endpoint.
Review violation reports and add legitimate sources until the policy is clean.
Switch to an enforcing Content-Security-Policy header at the CDN/server/Nginx layer.
Re-scan to confirm CSP is present and monitor for regressions after deploys.

Verify

Re-run the URL scan after deploying the change to confirm the issue clears and the Themerella Score updates.

Related guides

Continue the same website quality workflow.

Free Security Headers Checker How to Fix a Missing X-Frame-Options Header How to Fix a Missing HSTS Header