Claude Code
auth
CORS Wildcard Allow-Origin Too Permissive
CORS configured with Access-Control-Allow-Origin: * allowing any origin to access the API. Security audit flags this as a vulnerability. Any website can make requests to the API on behalf of users.
While allowing all origins is convenient for development, it's a security risk in production.
Error Messages You Might See
Security audit: CORS wildcard origin
OAuth token vulnerability from CORS misconfiguration
CSRF risk from overly permissive CORS
Common Causes
- Wildcard used for simplicity during development and never changed for production
- CORS allowed for all endpoints including sensitive ones
- Misunderstanding that wildcard is safe (it's not)
- No authentication on API endpoints, relying on origin restriction
- CORS configured globally without considering security implications
How to Fix It
Replace * with specific domains: Access-Control-Allow-Origin: https://trusted.example.com. For multiple domains: check Origin header, return specific domain if in whitelist. Only allow CORS for non-sensitive endpoints. Sensitive operations (delete, payment) should require stronger auth. Always combine with authentication (JWT tokens), don't rely on origin alone.
Real developers can help you.
Milan Surelia
Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems.
Expertise:
💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web.
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Notable Achievements:
🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX.
🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development.
🌟 Open source contributions on Github & StackOverflow for Flutter & Dart
🎖️ Worked on improving app performance and user experience with smart solutions.
Milan is always happy to connect, work on new ideas, and explore the latest in technology.
Costea Adrian
Embedded Engineer specilizing in perception systems. Latest project was a adas camera calibration system.
Jen Jacobsen
I’m a Full-Stack Developer with over 10 years of experience building modern web and mobile applications. I enjoy working across the full product lifecycle — turning ideas into real, well-built products that are intuitive for users and scalable for businesses.
I particularly enjoy building mobile apps, modern web platforms, and solving complex technical problems in a way that keeps systems clean, reliable, and easy to maintain.
Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale.
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PawelPloszaj
I'm fronted developer with 10+ years of experience with big projects. I have small backend background too
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I’m a product-focused engineer and tech leader who builds scalable systems and turns ideas into production-ready platforms.
Over the past years, I’ve worked across startups and fast-moving teams, leading backend architecture, improving system reliability, and shipping products used by thousands of users. My strength is not just writing code — but connecting product vision, technical execution, and business impact.
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Yovel Cohen
I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.
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I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures.
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My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.**
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Get HelpFrequently Asked Questions
Why is Access-Control-Allow-Origin: * unsafe?
Any website can make authenticated requests on user's behalf. If user logged in, attacker's site can call API as that user.
How to allow multiple specific origins?
Check Origin header. If in whitelist, return it: Access-Control-Allow-Origin: origin (where origin is the value sent).
Should sensitive APIs allow CORS?
No. CORS should only apply to read-only or public APIs. Sensitive operations (delete, payment) should require stronger auth.