Headers Security
low Severity
Free Check
Deprecated X-XSS-Protection Header
Checks that legacy X-XSS-Protection is set to 0 or removed to prevent browser XSS auditor vulnerabilities.
Why It Matters
The legacy XSS auditor in older browsers introduced security vulnerabilities and unintended side-channel leaks. Modern standard is CSP.
How We Check This
We check if X-XSS-Protection is either absent or set to 0 rather than 1; mode=block.
How to Fix & Implement
Copy-paste configuration blocks tailored for your web server or edge proxy.
nginx snippet
add_header X-XSS-Protection "0" always;
Frequently Asked Questions
Why shouldn’t I use X-XSS-Protection: 1; mode=block?
Modern browsers have deprecated the built-in auditor, and older implementations could be abused to block legitimate scripts.