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.

Test Your Website for Deprecated X-XSS-Protection Header

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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.