# Missing Security Headers

> Detects missing or misconfigured HTTP security headers that protect against common browser-based attacks.

- Skill: `zakirkun/missing-security-headers` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add zakirkun/missing-security-headers`
- Raw SKILL.md: https://api.skillmd.com/api/skills/zakirkun/missing-security-headers/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: zakirkun (https://skillmd.com/u/zakirkun)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/zakirkun/missing-security-headers

---


# Missing Security Headers

## Overview
HTTP security headers instruct the browser to enable additional protections. Missing headers expose applications to:
- **Missing HSTS**: Downgrade attacks, MITM on first connection
- **Missing CSP**: XSS amplification
- **Missing X-Content-Type-Options**: MIME sniffing attacks
- **Missing Referrer-Policy**: Sensitive URL leakage in Referer header
- **Missing Permissions-Policy**: Feature abuse (camera, microphone, geolocation)

## Recommended Headers
```
Strict-Transport-Security: max-age=31536000; includeSubDomains
Content-Security-Policy: default-src 'self'
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
Referrer-Policy: strict-origin-when-cross-origin
Permissions-Policy: geolocation=(), microphone=(), camera=()
```