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cors-cross-origin-misconfiguration

Identify exploitable CORS misconfigurations enabling cross-origin theft of authenticated user data.

96|1|Updated Jun 4, 2026
Search Tags:#security testing#penetration testing#cors#api security#web application security#jsonp hijacking#origin bypass
One-click install
npx skills add https://github.com/langbyyi/CyberStrikeAI-SRC --skill cors-cross-origin-misconfiguration-langbyyi
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: cors-cross-origin-misconfiguration
Source: https://github.com/langbyyi/CyberStrikeAI-SRC/tree/main/skills/cors-cross-origin-misconfiguration
Command: npx skills add https://github.com/langbyyi/CyberStrikeAI-SRC --skill cors-cross-origin-misconfiguration-langbyyi

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill addresses the critical risk of undetected CORS misconfigurations in web applications that enable attackers to steal authenticated user data via cross-origin requests, JSONP hijacking, and origin validation bypass techniques, gaps that are often missed in standard automated security scans.

Core Features & Use Cases

  • Multi-Vector CORS Testing: Covers reflected origin, null origin via sandboxed iframes, subdomain allowlist bypass, and preflight policy bug detection for comprehensive flaw identification across all common CORS misconfiguration types.
  • JSONP Hijacking Analysis: Identifies and provides exploitation payloads for JSONP endpoints with unvalidated callback parameters to demonstrate data theft risk from authenticated sessions.
  • Structured Testing Guidance: Includes a decision tree, step-by-step testing checklist, and references to integrated MCP tools to streamline authorized penetration testing engagements. Use case: Security teams use this Skill to audit web APIs and single-page applications during authorized security assessments to identify CORS flaws that could lead to large-scale user data breaches.

Quick Start

Use the cors-cross-origin-misconfiguration skill to test all authenticated JSON API endpoints on your target web application for exploitable CORS misconfigurations including reflected origins, null origin bypasses, and JSONP hijacking risks.

Frequently Asked Questions about cors-cross-origin-misconfiguration

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I test for CORS misconfigurations like reflected origin and null origin bypass?▼

You test CORS misconfigurations by validating header behavior against reflected origins, null origin bypasses via sandboxed iframes, and flawed allowlist implementations to confirm cross-origin data theft risks.

What is JSONP hijacking and how does it relate to cross-origin data theft?▼

JSONP hijacking is a cross-origin attack vector exploiting unvalidated callback parameters on JSONP endpoints to steal authenticated user data from active web application sessions.

How do I generate proof-of-concept payloads for authorized CORS security assessments?▼

You generate proof-of-concept payloads by building exploitation chains that demonstrate cross-origin data theft through reflected origins and subdomain allowlist bypasses during authorized security assessments.

Can I use this approach to audit single-page applications for API security flaws?▼

Yes, this approach supports auditing single-page applications by testing all authenticated JSON API endpoints for exploitable CORS misconfigurations and JSONP hijacking vulnerabilities.

Does standard automated security scanning detect flawed CORS allowlist implementations?▼

Standard automated security scans often miss flawed CORS allowlist implementations, requiring structured testing checklists and decision trees to identify subdomain bypass and preflight policy bugs.

When should I test for null origin bypass using sandboxed iframes?▼

You should test for null origin bypass using sandboxed iframes when evaluating web applications that implement overly permissive cross-origin policies or rely on null origin validation for API security.

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