Content Security Policy: The HTTP Header That Stops Most XSS

Cross-site scripting has been the most common web vulnerability for 25 years. Most attempts to stop it (sanitization, escaping, validation) work most of the time and fail in the cases that matter. Content Security Policy is the browser-level defense that says 'only run scripts I authorized' -- and when it's deployed correctly, it stops virtually every XSS attack. Most teams don't deploy it correctly.