Dries Buytaert

Explanation

The Cross-Origin-Resource-Policy header is part of the Fetch metadata request headers. It controls how resources can be shared across origins, enhancing security by preventing unauthorized access to resources.
Notice cross-origin means the resource can be loaded by documents from any origin. This is the least secure option.

The type of the message body, specified as a MIME type.

The date and time at which the request was made. A browser uses it for age calculations rather than using its own internal date and time; e.g. when comparing against Max-Age or Expires.

Identifies the software used by the origin server to handle the request (e.g. Apache, Nginx, Cloudflare).
Warning The server header exposes a version number (1.0). This makes it easier for attackers to find known vulnerabilities for that version. Remove or suppress the version number.

The size of the message body, in bytes.

This header enables the browser's built-in XSS protection. However, it's considered legacy and modern browsers may ignore it.
Notice While this header provides some protection, it's recommended to use Content-Security-Policy instead, as it offers more comprehensive and flexible protection against XSS and other injection attacks.

X-Frame-Options prevents this URL from being embedded in an iframe. This protects against clickjacking attacks.
sameorigin means that this page can be displayed in an iframe, but only on the current origin. It can't be displayed on another domain. Consider setting this to deny for added security.

The alt-svc header advertises alternative services for accessing the same resource, enabling protocol negotiation and potential performance improvements.
h3 indicates that HTTP/3 is supported. Variants like h3-29 refer to specific drafts of the HTTP/3 protocol.
ma=2592000 specifies that the alternative service information is fresh for 2592000 seconds.
ma=2592000 specifies that the alternative service information is fresh for 2592000 seconds.

missing Add a Strict-Transport-Security header. The Strict-Transport-Security header or HSTS header is used to instruct browsers to only use HTTPS, instead of using HTTP. It helps enforce secure communication.

missing Add a Content-Security-Policy header. The Content-Security-Policy header helps browsers prevent cross site scripting (XSS) and data injection attacks.

missing Add a Referrer-Policy header. When a visitor navigates from one page to another, browsers often pass along referrer information. The Referrer-Policy header controls how much referrer information a browser can share. This is important to configure when private information is embedded in the path or query string and passed onto an external destination.

missing Add a Permissions-Policy header. Restrict access to device features like the camera, microphone, location, accelerometer and much more.

missing Add a Cross-Origin-Embedder-Policy to specify how this page can be loaded by cross-origin resources.

missing Add a Cross-Origin-Opener-Policy header to opt-in into better browser isolation.

missing Add an X-Content-Type-Options: nosniff header to prevent browsers from MIME type sniffing. Without it, browsers may interpret files as a different content type than intended, which can lead to security vulnerabilities.

missing Add a X-Permitted-Cross-Domain-Policies header to prevent Flash, Adobe Reader and other clients from sharing data across domains.