X-XSS-Protection Checker — Legacy XSS Filter Header
Read checks.xXssProtection — legacy browser XSS filter header presence and value
How to Use This Tool
- Enter full public URL with https:// scheme.
- SSRF-safe fetch retrieves response headers.
- checks.xXssProtection maps from x-xss-protection header name.
- Present earns eleven score points; absent adds to missing array.
- recommendations may suggest 1; mode=block for legacy browsers.
- Review checks.csp for primary modern XSS mitigation status.
About This Tool
X-XSS-Protection enabled IE and older Chrome reflective XSS filters — modern guidance deprecates it in favor of strict Content-Security-Policy, but legacy compliance checklists still ask whether 1; mode=block is set. VSPIC X-XSS-Protection checker calls security-headers with your URL, surfacing checks.xXssProtection present flag, value preview, points, alongside full checks, grade, missing, recommendations, and headers map from the complete scan.
Treat this header as legacy defense-in-depth — checks.csp presence matters more for modern browsers. This page emphasizes checks.xXssProtection for audit questionnaires while returning full security-headers JSON identical to security-headers-checker and sibling single-header landing pages.
Common use cases
- •Inspect HTTP headers and user-agent strings
- •Analyze email headers for phishing investigation
- •Generate strong passwords for staging environments
Why use VSPIC for ?
- Explicit checks.xXssProtection for compliance audits.
- Full security-headers context — not header isolation without CSP view.
- Value truncation preview for mode=block verification.
- recommendations and missing arrays for remediation tickets.
- Grade shows broader header posture beyond legacy XSS header.
- Free scan — automate via security-headers API.
Legacy X-XSS-Protection role
Browsers once shipped reflective XSS filters triggered by X-XSS-Protection: 1; mode=block. Known bypasses and inconsistent behavior led MDN and OWASP to recommend relying on CSP instead. Some enterprise scanners still flag missing header — this page documents presence for those workflows.
checks.xXssProtection.value shows header content when set. Absence is often intentional on modern hardened sites with strict CSP.
Modern XSS mitigation priority
Content-Security-Policy script-src with nonces or hashes is primary defense. checks.csp in the same JSON response indicates CSP presence — prioritize CSP deployment over legacy XSS header for real security gain.
Missing xXssProtection with strong CSP may be correct modern posture — interpret grade holistically.
Relationship to security-headers-checker
All single-header missing-tool pages call action security-headers. x-xss-protection-checker emphasizes checks.xXssProtection SEO; security-headers-checker covers full scored audit.
API: GET /ip-tools/api/extended?action=security-headers&url=https://example.com
Compliance questionnaire context
Legacy PCI or internal checklists may ask for X-XSS-Protection explicitly. Export checks.xXssProtection.present and value in JSON attachments. Note CSP supersession in narrative when header intentionally omitted.
Auditors increasingly accept CSP-only posture — document rationale when missing.
Recommended values when required
If policy mandates header, use X-XSS-Protection: 1; mode=block. Avoid 0 unless disabling filter intentionally on pages with known false positives in ancient browsers.
Do not treat header as substitute for output encoding and CSP.
Reading score alongside legacy header
Eleven points when present — part of ninety-nine maxScore across nine categories. Missing xXssProtection alone does not fail entire audit when CSP and other checks present.
missing array lists xXssProtection among absent headers for ticket prioritization.
Platform deployment notes
Nginx add_header X-XSS-Protection "1; mode=block" always; on HTML locations. Remove when CSP matures — duplicate policies confuse maintainers.
Verify header on HTML document responses — API JSON endpoints may omit both XSS header and CSP appropriately.
Authorized use
Scan URLs you own or assess by contract. No active exploitation attempted — passive header read only.
We do not permanently store URL scans.
Important notes & limitations
- Legacy header — modern browsers ignore or deprecate XSS filter.
- Presence scoring does not validate CSP script-src strictness.
- Does not perform active XSS payload testing.
- Single document URL — not full site crawl.
- Some hosts omit header intentionally per modern best practice.
Frequently Asked Questions
Yes. VSPIC offers this X-XSS-Protection checker at no cost with no account required. Results load in real time.
We do not permanently store your queries on our servers. Some tools run entirely in your browser; others fetch public data for the request only.
Yes. Open the page in any modern phone or tablet browser. Results work on Wi‑Fi and mobile data.
Modern best practice prioritizes CSP. Legacy checklists may still ask for it — this page documents presence via checks.xXssProtection.
security-headers with the url parameter.
Not necessarily. Strong CSP is preferred. Missing legacy header with strict CSP may be intentional modern posture.
Same API and JSON. This page emphasizes checks.xXssProtection legacy header SEO.
No. It reads response headers only — no payload injection testing.
When required by policy: 1; mode=block. Prefer deploying strict Content-Security-Policy for modern browsers.
Next step for your check
Continue with security headers checker on VSPIC.
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