How to fix missing x frame options on BigCommerce

Steps for BigCommerce

1. BigCommerce sets some security headers automatically, but custom header configuration requires going through Cloudflare or another CDN/proxy in front of your store.
2. Log in to Cloudflare (or your CDN) → select your BigCommerce domain → go to Rules → Transform Rules → Response Header Modification.
3. Create a new rule: match all incoming requests (or specific paths like /checkout), action = Set header, Header name = X-Frame-Options, Value = SAMEORIGIN → Save and Deploy.
4. If you are not using Cloudflare, contact BigCommerce support to ask whether custom response headers can be set at the platform level for your plan.
5. Verify with browser DevTools or a header-checker after the CDN rule is live.

What is missing x frame options?

The X-Frame-Options header is a security instruction your web server sends to browsers telling them whether your pages are allowed to be loaded inside an iframe (an invisible "frame" embedded in another website). When this header is missing, any website in the world can silently embed your store inside their page. The two safe values are DENY (no framing at all) and SAMEORIGIN (only your own domain can frame your pages). Most stores should use SAMEORIGIN unless you have no legitimate need to embed your own pages in iframes, in which case DENY is even stronger.

Without X-Frame-Options, attackers can use a technique called "clickjacking" — they overlay your store's checkout or login page inside an invisible iframe on a malicious site, tricking shoppers into clicking buttons they can't see. This can lead to unauthorized purchases, stolen account credentials, or fraudulent transactions, directly costing you revenue and eroding customer trust. Search engines and security scanners flag this missing header as a vulnerability under OWASP A05:2021 (Security Misconfiguration), which can affect your site's security rating and enterprise buyer trust. Many payment card industry (PCI DSS) compliance checklists also require it, so missing it can jeopardize your ability to process card payments.

See the complete Missing x frame options guide for every platform and the full background.