Content-Security-Policy header missing: what it is, why it matters, and how to fix it
This site does not send a Content-Security-Policy (CSP) HTTP header. CSP restricts which sources the browser can load scripts, styles, images, and other resources from, providing strong protection against cross-site scripting (XSS) attacks.
Where this fits: security in SEO
Why content-security-policy header missing hurts your rankings
Without CSP, the page is more vulnerable to XSS attacks, where attackers inject malicious scripts that can steal user data, session tokens, or redirect users to phishing sites. While CSP is not a direct SEO ranking factor, a security breach can lead to your site being flagged as malicious by Google Safe Browsing, which results in dramatic traffic loss and a warning interstitial in Chrome. Prevention is far easier than recovery.
This is a low-severity issue: a polish item. Fix it in batches during scheduled maintenance; the win is cumulative quality, not a step change.
How to fix it
Implement a Content-Security-Policy header that restricts resource loading to trusted sources. Start with a report-only policy (Content-Security-Policy-Report-Only) to identify violations before enforcing. Use nonces or hashes for inline scripts rather than 'unsafe-inline'.
# Basic CSP header
Content-Security-Policy: default-src 'self'; script-src 'self' https://trusted-cdn.com; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' https://fonts.gstatic.com;
# Report-only mode for testing
Content-Security-Policy-Report-Only: default-src 'self'; report-uri /csp-report-endpointFrequently asked questions
What does "Content-Security-Policy header missing" mean?
This site does not send a Content-Security-Policy (CSP) HTTP header. CSP restricts which sources the browser can load scripts, styles, images, and other resources from, providing strong protection against cross-site scripting (XSS) attacks.
Why does content-security-policy header missing matter for SEO?
Without CSP, the page is more vulnerable to XSS attacks, where attackers inject malicious scripts that can steal user data, session tokens, or redirect users to phishing sites. While CSP is not a direct SEO ranking factor, a security breach can lead to your site being flagged as malicious by Google Safe Browsing, which results in dramatic traffic loss and a warning interstitial in Chrome. Prevention is far easier than recovery.
How do I fix content-security-policy header missing?
Implement a Content-Security-Policy header that restricts resource loading to trusted sources. Start with a report-only policy (Content-Security-Policy-Report-Only) to identify violations before enforcing. Use nonces or hashes for inline scripts rather than 'unsafe-inline'.
How serious is this issue?
This is a low-severity issue: a polish item. Fix it in batches during scheduled maintenance; the win is cumulative quality, not a step change. It belongs to the security family of checks.
How do I find every page affected by this on my site?
Run a free Dr Urls audit: it crawls your site, detects content-security-policy header missing on every affected page, shows example URLs, and generates a ready-to-use fix task. Re-scan after fixing to verify the issue is gone.
Does your site have this issue?
A free Dr Urls audit crawls your site, finds every page affected by content-security-policy header missing, and hands you a ready-made fix task.
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