{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:fastify:fastify\\/middie:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "9.3.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "792d2f46ae68516d3122c9a4468a5748a34efb47"
            }
          ],
          "repo": "https://github.com/fastify/middie",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-436"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6270.json"
  },
  "details": "@fastify/middie versions 9.3.1 and earlier do not register inherited middleware directly on child plugin engine instances. When a Fastify application registers authentication middleware in a parent scope and then registers child plugins with @fastify/middie, the child scope does not inherit the parent middleware. This allows unauthenticated requests to reach routes defined in child plugin scopes, bypassing authentication and authorization checks. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds.",
  "id": "CVE-2026-6270",
  "modified": "2026-07-08T05:37:40.679115219Z",
  "published": "2026-04-16T13:44:46.322Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6270.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/fastify/middie/security/advisories/GHSA-72c6-fx6q-fr5w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6270"
    }
  ],
  "related": [
    "GHSA-hrwm-hgmj-7p9c",
    "GHSA-72c6-fx6q-fr5w"
  ],
  "schema_version": "1.7.5",
  "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 middleware authentication bypass in child plugin scopes"
}