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
Security audit: CORS wildcard originOAuth token vulnerability from CORS misconfigurationCSRF risk from overly permissive CORS

Common Causes

  1. Wildcard used for simplicity during development and never changed for production
  2. CORS allowed for all endpoints including sensitive ones
  3. Misunderstanding that wildcard is safe (it's not)
  4. No authentication on API endpoints, relying on origin restriction
  5. 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 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. 🖋️ Sharing insights through technical writing, blogging, and open-source contributions. 🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences. 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. Alvin Voo Alvin Voo I’ve watched the tech landscape evolve over the last decade—from the structured days of Java Server Pages to the current "wild west" of Agentic-driven development. While AI can "vibe" a frontend into existence, I specialize in the architecture that keeps it from collapsing. My expertise lies in the critical backend infrastructure: the parts that must be fast, secure, and scalable. I thrive on high-pressure environments, such as when I had only three weeks to architect and launch an Ethereum redemption system with minimal prior crypto knowledge, turning it into a major revenue stream. What I bring to your project: Forensic Debugging: I don't just "patch" bugs; I use tools like Datadog and Explain Analyzers to map out bottlenecks and resolve root causes—like significantly reducing memory usage by optimizing complex DB joins. Full-Stack Context: Deep experience in Node.js and React, ensuring backends play perfectly with mobile and web teams. Sanity in the Age of AI: I bridge the gap between "best practices" and modern speed, ensuring your project isn't just built fast, but built to last. Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. Taufan Taufan 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. Victor Denisov Victor Denisov Developer Prakash Prajapati Prakash Prajapati I’m a Senior Python Developer specializing in building secure, scalable, and highly available systems. I work primarily with Python, Django, FastAPI, Docker, PostgreSQL, and modern AI tooling such as PydanticAI, focusing on clean architecture, strong design principles, and reliable DevOps practices. I enjoy solving complex engineering problems and designing systems that are maintainable, resilient, and built to scale. rayush33 rayush33 JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems Simon A. Simon A. I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows. Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services David Olverson David Olverson Solo dev shipping production apps with AI-assisted development. I specialize in rescuing broken Lovable/Bolt/Cursor builds and taking them to production. 10+ apps shipped including SaaS CRMs, gaming platforms, real estate tools, and Discord bots. Stack: Next.js 16, TypeScript, Tailwind CSS, FastAPI, PostgreSQL, Prisma. I use Claude Code with 50+ custom skills for rapid delivery. Average turnaround: 2-4 weeks from broken prototype to production.

You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.

Get Help

Frequently 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.

Related Claude Code Issues

Can't fix it yourself?
Real developers can help.

You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.

Get Help