CVE-2026-33011: Nest Fastify HEAD Request Middleware Bypass
Impact
In a NestJS application using @nestjs/platform-fastify, GET middleware can be bypassed because Fastify automatically redirects HEAD requests to the corresponding GET handlers (if they exist).
As a result:
- Middleware will be completely skipped. - The HTTP response won't include a body (since the response is truncated when redirecting a HEAD request to a GET handler). - The actual handler will still be executed.
Patches
Fixed in @nestjs/platform-fastify@11.1.16
Other sources
Nest is a framework for building scalable Node.js server-side applications. In versions 11.1.15 and below, a NestJS application using @nestjs/platform-fastify GET middleware can be bypassed because Fastify automatically redirects HEAD requests to the corresponding GET handlers (if they exist). As a result: middleware will be completely skipped, the HTTP response won't include a body (since the response is truncated when redirecting a HEAD request to a GET handler), and the actual handler will still be executed. This issue is fixed in version 11.1.16.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33011?
The CVE-2026-33011 vulnerability is considered to have a moderate severity due to its ability to bypass middleware in NestJS applications.
How do I fix CVE-2026-33011?
To fix CVE-2026-33011, update the @nestjs/platform-fastify package to version 11.1.16 or later.
What type of applications are affected by CVE-2026-33011?
CVE-2026-33011 affects NestJS applications using the @nestjs/platform-fastify package.
What specific feature of Fastify contributes to CVE-2026-33011?
CVE-2026-33011 is caused by Fastify automatically redirecting HEAD requests to their corresponding GET handlers, bypassing middleware.
What are the potential consequences of CVE-2026-33011?
The potential consequences of CVE-2026-33011 include skipped middleware execution and changes to the expected HTTP response.