CVE-2026-33011: @nestjs/platform fastify Nest Fastify HEAD Request Middleware Vulnerability

HIGH
Advisory Identifier: GHSA-wf42-42fg-fg84
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CWE-670
Published
Advisory Summary

CVE-2026-33011 is a HIGH nest fastify head request middleware vulnerability (CWE-670: Always-Incorrect Control Flow Implementation) affecting @nestjs/platform fastify libraries in the npm ecosystem. The issue involves nest fastify head request middleware bypass. Remediation is available by upgrading affected packages to version 11.1.16.

CVE-2026-33011 at a Glance

CVE Identifier CVE-2026-33011
GHSA Identifier GHSA-wf42-42fg-fg84
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-670: Always-Incorrect Control Flow Implementation
Affected Product @nestjs/platform fastify
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-33011

To remediate this vulnerability, upgrade all affected @nestjs/platform fastify dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@nestjs/platform-fastify fixed: 11.1.16 
npm install @nestjs/platform-fastify@11.1.16
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @nestjs/platform-fastify

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-33011, inspect your project dependencies using npm:

npm ls @nestjs/platform-fastify

Analyze the terminal output to locate any version of @nestjs/platform fastify in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 11.1.16), your application is affected.

Note: The npm ls @nestjs/platform-fastify command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-670: Always-Incorrect Control Flow Implementation, where the code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated. In @nestjs/platform fastify, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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`

CVE-2026-33011 Affected @nestjs/platform fastify Versions

1 component(s)
Fixed Versions:
11.1.16
Product / Package Ecosystem Affected Versions Fixed Version
@nestjs/platform-fastify
npm/@nestjs/platform-fastify
npm
< 11.1.16
11.1.16

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nestjs/nest/security/advisories/GHSA-wf42-42fg-fg84
NVD — CVE-2026-33011 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33011
Security Fix Commit FIX COMMIT
https://github.com/nestjs/nest/commit/cbdf737cd6e7cefa52d05ecea2ae4af95c464614
@nestjs/platform fastify Source Repository REPOSITORY
https://github.com/nestjs/nest
@nestjs/platform fastify Release RELEASE
https://github.com/nestjs/nest/releases/tag/v11.1.17

Frequently Asked Questions

What is CVE-2026-33011?
CVE-2026-33011 is a security vulnerability in @nestjs/platform fastify involving Nest Fastify HEAD Request Middleware Bypass under CWE-670: Always-Incorrect Control Flow Implementation.
Which @nestjs/platform fastify versions are affected?
Affected versions include releases prior to 11.1.16 across affected packages: @nestjs/platform-fastify.
What version fixes CVE-2026-33011?
Upgrading to 11.1.16 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @nestjs/platform-fastify affected?
Yes, @nestjs/platform-fastify is affected in releases prior to 11.1.16. Upgrade your dependency to 11.1.16 or later.
What CWE is associated with CVE-2026-33011?
CVE-2026-33011 is classified under CWE-670: Always-Incorrect Control Flow Implementation (The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.).
How can I check npm dependencies for CVE-2026-33011?
Run the dependency tree command: 'npm ls @nestjs/platform-fastify'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wf42-42fg-fg84",
  "modified" : "2026-03-20T21:21:43Z",
  "published" : "2026-03-17T18:38:38Z",
  "aliases" : [ "CVE-2026-33011" ],
  "summary" : "Nest Fastify HEAD Request Middleware Bypass",
  "details" : "### Impact\n\nIn 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).\n\nAs a result:\n\n- Middleware will be completely skipped.\n- The HTTP response won't include a body (since the response is truncated when redirecting a HEAD request to a GET handler).\n- The actual handler will still be executed.\n\n### Patches\n\nFixed in `@nestjs/platform-fastify@11.1.16`",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nestjs/platform-fastify"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "11.1.16"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 11.1.15"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nestjs/nest/security/advisories/GHSA-wf42-42fg-fg84"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33011"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nestjs/nest/commit/cbdf737cd6e7cefa52d05ecea2ae4af95c464614"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nestjs/nest"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nestjs/nest/releases/tag/v11.1.17"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-670" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-17T18:38:38Z",
    "nvd_published_at" : "2026-03-20T05:16:15Z"
  }
}