{
  "schemaVersion": "guard-threat-campaign/v1",
  "id": "HGTC-2026-21EC3D3F",
  "slug": "cve-2026-85184-fastify-middie-absolute-form-middleware-bypass",
  "title": "Fastify middie absolute-form requests can skip auth",
  "aliases": [
    "CVE-2026-85184",
    "@fastify/middie absolute-form bypass"
  ],
  "summary": "@fastify/middie before 9.3.4 allows absolute-form requests to skip path-scoped middleware auth. Upgrade to 9.3.4.",
  "status": "published",
  "severity": "critical",
  "confidence": "high",
  "uncertainty": "Confirm whether your app uses path-scoped middie middleware.",
  "firstObservedAt": "2026-09-04T00:00:00.000Z",
  "lastObservedAt": "2026-09-04T12:00:00.000Z",
  "publishedAt": "2026-09-20T19:37:33.351Z",
  "reviewedAt": "2026-09-20T19:37:27.931Z",
  "expiresAt": "2026-09-04T12:00:00.000Z",
  "reviewer": "HOL Guard Security Publishing",
  "sources": [
    {
      "id": "ghsa",
      "label": "GitHub Security Advisory GHSA-hx87-8wv7-pjv8",
      "url": "https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8",
      "sourceType": "maintainer_advisory",
      "observedAt": "2026-09-04T12:00:00.000Z"
    },
    {
      "id": "nvd",
      "label": "NVD CVE-2026-85184",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85184",
      "sourceType": "vulnerability_database",
      "observedAt": "2026-09-04T12:00:00.000Z"
    },
    {
      "id": "hol-blog",
      "label": "HOL Guard operator write-up",
      "url": "https://hol.org/blog/cve-2026-85184-fastify-middie-absolute-form-middleware-bypass",
      "sourceType": "other_primary",
      "observedAt": "2026-09-04T12:00:00.000Z"
    }
  ],
  "artifacts": [
    {
      "id": "fastify-middie",
      "artifactClass": "package",
      "ecosystem": "npm",
      "name": "@fastify/middie",
      "version": ">=9.1.0 <9.3.4",
      "defanged": false
    }
  ],
  "indicators": [],
  "timeline": [
    {
      "id": "disclosure",
      "occurredAt": "2026-09-04T00:00:00.000Z",
      "eventType": "disclosure",
      "summary": "CVE-2026-85184 @fastify/middie absolute-form middleware bypass disclosed.",
      "sourceIds": [
        "ghsa",
        "nvd"
      ]
    },
    {
      "id": "hol-publish",
      "occurredAt": "2026-09-04T12:00:00.000Z",
      "eventType": "other",
      "summary": "HOL Guard published operator coverage for CVE-2026-85184.",
      "sourceIds": [
        "hol-blog"
      ]
    }
  ],
  "coverage": [],
  "policies": [],
  "limitations": [
    "Scoped to absolute-form request + path-scoped middie middleware.",
    "Fixed version 9.3.4 from GHSA.",
    "HOL blog is operator guidance."
  ],
  "correctionHref": "/guard/security/campaigns/cve-2026-85184-fastify-middie-absolute-form-middleware-bypass/corrections"
}