CVE-2026-33011: NestJS platform-fastify HEAD request middleware bypass

CVE-2026-33011 · Severity: medium · CVSS 4 · Published 2026-03-17

NestJS is a popular Node.js framework for building server applications. The Fastify adapter (platform-fastify) contains a security flaw where HTTP HEAD requests bypass middleware security checks while still executing application handlers. This allows attackers to circumvent authentication, authorization, logging, and other protective middleware layers that guard sensitive operations.

Technologies: NestJS Platform-Fastify, @nestjs/platform-fastify (npm). Vendors: NestJS, npm.

Quick answers

Is CVE-2026-33011 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33011 being exploited in the wild.
How severe is CVE-2026-33011?
Medium severity, with a CVSS score of 4, published 17 March 2026.
Which products and versions are affected?
NestJS Platform-Fastify < 11.1.16; @nestjs/platform-fastify (npm) SEMVER:introduced=0,fixed=11.1.16.
Is there a fix for CVE-2026-33011?
Yes. @nestjs/platform-fastify (npm): upgrade to 11.1.16 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33011 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-33011?
Check whether you run NestJS Platform-Fastify or @nestjs/platform-fastify (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • @nestjs/platform-fastify (npm): upgrade to 11.1.16 or later
    npm install @nestjs/platform-fastify@11.1.16

Technical details

The vulnerability is a middleware bypass flaw (CWE-670) in @nestjs/platform-fastify where Fastify automatically redirects HEAD requests to corresponding GET handlers. When this occurs, NestJS middleware attached to GET routes is skipped entirely, while the underlying route handler still executes. The attack vector is network-based with no authentication or user interaction required. An attacker can send HEAD requests to GET endpoints to bypass security middleware (authentication, authorization, rate limiting, logging) while still triggering the handler logic. The vulnerability affects all versions up to 11.1.15; it is fixed in 11.1.16 and later.

Affected products

  • NestJS platform-fastify < 11.1.16

Identifiers

  • CVE-2026-33011
  • GHSA-wf42-42fg-fg84

Timeline

  • 2026-03-16: disclosed
  • 2026-03-17: advisory
  • 2026-03-17: patched: Fixed in @nestjs/platform-fastify 11.1.16

References

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