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          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/@fastify/express",
          "product": "@fastify/express",
          "vendor": "@fastify/express",
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              "lessThan": "4.0.9",
              "status": "affected",
              "version": "4.0.5",
              "versionType": "semver"
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      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "agent-killjoy"
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        {
          "lang": "en",
          "type": "remediation developer",
          "value": "mcollina"
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        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "UlisesGascon"
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          "lang": "en",
          "supportingMedia": [
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              "value": "@fastify/express is a Fastify plugin that runs Express middleware inside Fastify. In versions 4.0.5 through 4.0.8, when Fastify runs with the non-default ignoreDuplicateSlashes option enabled, the plugin matches path-scoped Express middleware against a URL whose duplicate-slash normalization has also collapsed the separator after an absolute-form request target\u0027s scheme, so Fastify\u0027s router resolves the request to the scoped path and runs the handler while the Express layer no longer sees that path. As a result, a request using an absolute-form target can reach a handler on a scoped route such as an admin path while the middleware for authentication, authorization, or rate limiting is skipped. An unauthenticated attacker needs only the non-default ignoreDuplicateSlashes option to be enabled. The issue is fixed in @fastify/express 4.0.9, and users should upgrade to 4.0.9 or later. As a workaround, enforce authentication in a Fastify hook such as preHandler that runs after the router resolves the request, or leave ignoreDuplicateSlashes at its default."
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        }
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      "metrics": [
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          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
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          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
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      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-436",
              "description": "CWE-436: Interpretation Conflict",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-27T11:27:59.364Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://github.com/fastify/fastify-express/security/advisories/GHSA-6h42-57hq-9746"
        },
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "@fastify/express vulnerable to path-scoped middleware bypass via absolute-form request targets",
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  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-112362",
    "datePublished": "2026-10-27T11:27:59.364Z",
    "dateReserved": "2026-10-19T14:59:03.468Z",
    "dateUpdated": "2026-10-27T11:27:59.364Z",
    "state": "PUBLISHED"
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