Content Security Policy (CSP) is a security mechanism designed to mitigate cross-site scripting attacks by disabling dangerous behaviours such as untrusted JavaScript execution. Websites can specify their security policy in a response header or meta tag, enabling fine-grained control over dangerous features like scripts and stylesheets.
Mitigate cross-site scripting by avoiding 'unsafe-inline', 'unsafe-eval', data: URLs, and global wildcards in script directives. Use a secure, random nonce of at least 8 characters 'nonce-RANDOM' to prevent untrusted JavaScript execution.