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Blog de Seguridad de Cabeceras

Guías en lenguaje sencillo para entender, implementar y corregir cabeceras de seguridad HTTP. escáner.

Header Guide

Cache-Control: Protecting Sensitive Data

Proper caching is great for performance, but dangerous for security. Learn how to stop browsers and proxies from storing sensitive pages.

Jun 21, 20264 min
Header Guide

Content-Type: More Than Just Meta Data

Setting the Content-Type correctly is vital. If an image is processed as HTML, it can lead directly to XSS vulnerabilities.

Jun 21, 20264 min
Header Guide

COOP, COEP, and CORP: Modern Cross-Origin Isolation

Learn how the holy trinity of cross-origin headers protects your application against advanced CPU side-channel attacks like Spectre.

Jun 21, 20264 min
Header Guide

Expect-CT: Why It's Time to Remove It

The Expect-CT header was useful for enforcing Certificate Transparency, but modern browsers now mandate it by default. Here's why you should delete it.

Jun 21, 20265 min
Header Guide

Opting Out of FLoC (Federated Learning of Cohorts)

Protect your users' privacy by explicitly opting your site out of Google's controversial FLoC tracking system.

Jun 21, 20263 min
Header Guide

Public-Key-Pins (HPKP): A Cautionary Tale

HTTP Public Key Pinning (HPKP) was a powerful security header that backfired spectacularly. Learn why it was deprecated and what replaced it.

Jun 21, 20264 min
Header Guide

Secure File Download Headers

When serving user-uploaded files, you must ensure they don't accidentally execute malicious code in the browser. Here are the headers you need.

Jun 21, 20264 min
Header Guide

Set-Cookie: Hardening Session Management

While not strictly a security header, the security flags attached to your cookies are the only thing preventing catastrophic session hijacking.

Jun 21, 20264 min
Header Guide

Server Fingerprinting: Server, X-Powered-By, and X-AspNet

Exposing your tech stack makes it incredibly easy for attackers to find vulnerabilities. Learn how to remove informative headers.

Jun 21, 20264 min
Header Guide

X-Content-Type-Options: Stopping MIME Sniffing

Browsers love to guess what type of file they are downloading. Learn how the nosniff directive prevents MIME confusion attacks.

Jun 21, 20264 min
Header Guide

X-DNS-Prefetch-Control: Stopping Data Leaks

Browsers proactively resolve domain names to speed up page loads. Here's why you might want to turn that off.

Jun 21, 20264 min
Header Guide

X-Robots-Tag: Controlling Crawlers Securely

Ensure sensitive documents like PDFs or internal datasets stay out of Google Search by mastering the X-Robots-Tag HTTP header.

Jun 21, 20264 min
Header Guide

X-XSS-Protection: Why You Should Turn It Off

The X-XSS-Protection header used to be a best practice, but modern browsers have removed it. Learn why setting it to 0 is now the standard.

Jun 21, 20265 min
Header Guide

Referrer-Policy: Choosing the Right Value

Referrer-Policy controls how much of your URL gets shared when users navigate away from your site. Here's what each value means and which one to use.

Mar 24, 20265 min
Troubleshooting

Why Your Site is Stuck at Grade B (Most Common Misses)

Getting an A on a security header scan isn't hard - but several specific issues commonly cap sites at B or C. Here's what to check.

Mar 17, 20265 min
Platform Guide

Security Headers Checklist for WordPress

How to add all six essential HTTP security headers to a WordPress site - using a plugin, your theme's functions.php, or your web server config (Nginx/Apache).

Mar 10, 20265 min
Comparison

Best Security Header Scanners Compared (2026)

A fair comparison of the top free HTTP security header scanners: SecHead, Mozilla Observatory, securityheaders.com, and others. What each one checks and where each shines.

Mar 3, 20265 min
Platform Guide

Security Headers Checklist for Next.js and Vercel

How to set all security headers in a Next.js application deployed on Vercel - using next.config.js, middleware, or vercel.json.

Feb 24, 20264 min
Header Guide

Permissions-Policy: What to Disable and Why

Permissions-Policy controls which browser APIs your page and embedded iframes can use. Here's what each feature does, which to block by default, and how to write the header.

Feb 17, 20266 min
Header Guide

X-Frame-Options vs frame-ancestors: What's the Difference?

Both X-Frame-Options and the CSP frame-ancestors directive protect against clickjacking. Learn which one to use, how they differ, and when to use both.

Feb 10, 20265 min
SEO

Do Security Headers Affect SEO Rankings?

Security headers don't directly improve your search rankings - but they affect Core Web Vitals, user trust signals, and crawl behavior in ways that do. Here's the real connection.

Feb 3, 20266 min
How-To

How to Fix 'unsafe-inline' in Your CSP

unsafe-inline in script-src disables most of CSP's XSS protection. This step-by-step guide shows you how to remove it using nonces or hashes without breaking your site.

Jan 27, 20265 min
Header Guide

Content-Security-Policy Explained for Beginners

CSP is the most powerful security header - and the most misunderstood. This guide explains what it does, how to write a policy, and the most common mistakes.

Jan 20, 20266 min
Header Guide

What is HSTS and Why Every Site Needs It

HSTS (HTTP Strict Transport Security) forces browsers to always use HTTPS. Here's what it does, why it matters, and the exact header value to use.

Jan 13, 20265 min
Pillar Guide

The Complete Security Headers Checklist (2026)

Every HTTP security header your site should have, what each one does, and the exact values to use. The definitive reference for developers and sysadmins.

Jan 6, 20265 min

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