VDB
KO
HIGH

GHSA-6v32-fjc9-9qf6

Nest: Middleware Bypass on Fastify via Trailing Slash

Details

### Impact

An authentication bypass vulnerability exists in `@nestjs/platform-fastify` (confirmed on version `11.1.24`, the latest available release at time of report). When middleware is registered through NestJS's `MiddlewareConsumer.forRoutes()` API on the Fastify adapter, an unauthenticated client can bypass the Nest middleware registered for that route by simply appending a trailing slash (`/`) to the request URL.

This bypass works on the **default Fastify adapter configuration** — no special router options need to be enabled. Applications using the standard CRUD route shape (`GET /resource` and `GET /resource/:id`) are affected when they protect those routes with `MiddlewareConsumer.forRoutes()` middleware.

### Patches

Fixed in `@nestjs/platform-fastify@11.1.24`

### References

Kudos goes to @a-tt-om

Are you affected?

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Affected packages

npm / @nestjs/platform-fastify
Introduced in: 0 Fixed in: 11.1.24
Fix npm install @nestjs/platform-fastify@11.1.24

References