PREQUEL-2025-0012
GraphQL internal server error due to unhandled exception in NestJS resolverMediumImpact: 6/10Mitigation: 5/10
Description
The application is generating internal server errors during GraphQL operations due to uncaught exceptions in resolver logic. These errors are not properly handled or transformed into structured GraphQL responses, resulting in unexpected 500-level failures for client applications. Stack traces often reference NestJS internal files like `external-context-creator.js`, indicating the framework attempted to execute resolver logic but encountered an exception that was not intercepted by the application code.\n
Mitigation
- Wrap resolver logic in try/catch blocks and use structured error handling\n- Use NestJS `@Catch()` exception filters or global error handlers to format exceptions consistently\n- Validate and sanitize all resolver input to avoid type or runtime errors\n- Return `GraphQLError` or Apollo-formatted errors instead of raw exceptions\n- Ensure proper typing in resolvers to avoid returning `undefined` for non-nullable fields\n- Add error boundaries around external calls or IO to catch downstream failures\n- Integrate structured logging to capture resolver-level exceptions with context\n