Windsurf api

Cascade Broke Webhook Signature Validation

Webhook signature validation is broken after Cascade refactored the verification code. This is a critical security issue - spoofed webhooks from attackers are being accepted as legitimate. Stripe or other webhook payloads are not being verified before processing.

Cascade likely removed or modified the signature verification logic during refactoring.

Error Messages You Might See

Webhook signature invalid HMAC verification failed Signature mismatch Webhook authenticity could not be verified
Webhook signature invalidHMAC verification failedSignature mismatchWebhook authenticity could not be verified

Common Causes

  1. Cascade removed HMAC-SHA256 signature verification from webhook handler
  2. Webhook secret changed without updating verification code
  3. Cascade removed timestamp validation preventing replay attacks
  4. Algorithm mismatch in signature generation vs verification

How to Fix It

Implement webhook signature verification immediately. Verify request body signature against webhook secret using HMAC-SHA256. Validate timestamp is recent (within 5 minutes) to prevent replay attacks. Verify algorithm used matches webhook provider documentation. Test with invalid signature to ensure rejection.

Real developers can help you.

Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services Jen Jacobsen 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. Tejas Chokhawala Tejas Chokhawala Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript. Focused on performance, clean architecture and shipping fast. Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools. Jaime Orts-Caroff Jaime Orts-Caroff I'm a Senior Android developer, open to work in various fields 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: šŸ’” Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web. šŸ–‹ļø Sharing insights through technical writing, blogging, and open-source contributions. šŸ¤ Collaborating closely with designers, PMs, and developers to build seamless mobile experiences. Notable Achievements: šŸŽÆ Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX. šŸš€ Launched Compose101 — a Jetpack Compose starter kit to speed up Android development. 🌟 Open source contributions on Github & StackOverflow for Flutter & Dart šŸŽ–ļø 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. Anthony Akpan Anthony Akpan Developer with 8 years of experience building softwares fro startups Luca Liberati Luca Liberati I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture Rudra Bhikadiya Rudra Bhikadiya I build and fix web apps across Next.js, Node.js, and DBs. Comfortable jumping into messy code, broken APIs, and mysterious bugs. If your project works in theory but not in reality, I help close that gap. Yovel Cohen 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. AUXLE AUXLE I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies.

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Frequently Asked Questions

How do I verify Stripe webhooks?

Use stripe.webhooks.constructEvent() with endpoint secret. Catches signature verification and parsing.

What timestamp validation should I do?

Verify t parameter is within last 5 minutes to prevent replay. Check against current system time.

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