CORS (Cross-Origin Resource Sharing) misconfiguration auditor. Probes any API endpoint with crafted Origin headers to detect the most dangerous CORS vulnerabilities — reflecting arbitrary Origins (any attacker.com gets CORS approved), Access-Control-Allow-Credentials:true with wildcard ACAO, null-Origin allowed (iframe/file:// bypass), subdomain regex bypasses (evil.myapp.com passes), missing Vary:Origin (CDN cache poisoning), and permissive preflight responses. Also scans source code for insecure CORS middleware patterns (Express/FastAPI/Go/Rails/Django/Spring). Generates correct CORS configuration for your specific stack. Works against any live URL via curl — zero external API. Triggers on "CORS error", "CORS misconfiguration", "Access-Control-Allow-Origin", "cors policy", "preflight", "cors blocked", "/cors-audit".
Install with
Claude CodeCodexCursorGitHub CopilotGemini CLI
Supported by the Atlas install prompt. Skill-specific requirements vary.
Skill stats
Skills1CategorySecurityStars0
About this skill
CORS (Cross-Origin Resource Sharing) misconfiguration auditor. Probes any API endpoint with crafted Origin headers to detect the most dangerous CORS vulnerabilities — reflecting arbitrary Origins (any attacker.com gets CORS approved), Access-Control-Allow-Credentials:true with wildcard ACAO, null-Origin allowed (iframe/file:// bypass), subdomain regex bypasses (evil.myapp.com passes), missing Vary:Origin (CDN cache poisoning), and permissive preflight responses. Also scans source code for insecure CORS middleware patterns (Express/FastAPI/Go/Rails/Django/Spring). Generates correct CORS configuration for your specific stack. Works against any live URL via curl — zero external API. Triggers on "CORS error", "CORS misconfiguration", "Access-Control-Allow-Origin", "cors policy", "preflight", "cors blocked", "/cors-audit".
Quick start
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CORS (Cross-Origin Resource Sharing) misconfiguration auditor. Probes any API endpoint with crafted Origin headers to detect the most dangerous CORS vulnerabilities — reflecting arbitrary Origins (any attacker.com gets CORS approved), Access-Control-Allow-Credentials:true with wildcard ACAO, null-Origin allowed (iframe/file:// bypass), subdomain regex bypasses (evil.myapp.com passes), missing Vary:Origin (CDN cache poisoning), and permissive preflight responses. Also scans source code for insecure CORS middleware patterns (Express/FastAPI/Go/Rails/Django/Spring). Generates correct CORS configuration for your specific stack. Works against any live URL via curl — zero external API. Triggers on "CORS error", "CORS misconfiguration", "Access-Control-Allow-Origin", "cors policy", "preflight", "cors blocked", "/cors-audit".
About this listing
Category
Security
Reported license
MIT
Listing language (estimated)
English
Review status
Not individually reviewed
Agent compatibility
Atlas installation supports Claude Code, Codex, and Cursor. Skill-specific dependencies and features are checked during setup.
Claude Code
Codex
Cursor
GitHub Copilot
Gemini CLI