{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "9.0.0"
                  },
                  {
                    "fixed": "9.3.6"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          },
          "events": [
            {
              "introduced": "d733838f145ebd88f5512aeab90784b957d8820a"
            },
            {
              "fixed": "a12f533be70adc06a6eed3566023c05b029e277e"
            }
          ],
          "repo": "https://github.com/fastify/middie",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-5p92-8765-9fv8"
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-436"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/112xxx/CVE-2026-112712.json"
  },
  "details": "@fastify/middie is the Express-style middleware engine for Fastify. In versions from 9.0.0 through 9.3.5, the use() function joined a path-scoped middleware's mount path to the plugin scope prefix in a way that could diverge from the path Fastify's router serves, most often when the scope prefix ended in a slash, and also for array mount paths and for mount paths written without a leading slash. When the two paths disagreed, the middleware was silently skipped while the route handler still ran, so path-scoped middleware such as authentication, authorization, or rate limiting could be bypassed by a single unauthenticated request. The issue is fixed in @fastify/middie 9.3.6, and users should upgrade to 9.3.6 or later. As a workaround, enforce authorization in a Fastify hook such as preHandler that runs after the router has resolved the request.",
  "id": "CVE-2026-112712",
  "modified": "2026-10-21T10:30:50.650859974Z",
  "published": "2026-10-20T20:43:48.681Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/112xxx/CVE-2026-112712.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/fastify/middie/security/advisories/GHSA-5p92-8765-9fv8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112712"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "@fastify/middie vulnerable to path-scoped middleware bypass via scope prefix mismatch"
}