X-XSS-Protection header not found

Rule from http under security category

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Some browsers have and anti-XSS filter which protects against certain classes of cross-site scripting attacks. This HTTP header configures the built in protection. The recommended value:

X-XSS-Protection: 1; mode=block

1 turns it on and mode=block ensures that the browser drops the request instead of trying to sanitize it.

How do I fix this ?

Although you may set http headers in your application code it is often simpler to configure the web server to set it properly.

// nginx
add_header X-XSS-Protection "1; mode=block";

// apache
<IfModule mod_headers.c>
  Header set X-XSS-Protection: "1; mode=block"


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