CVE-2026-45669: Nuxt Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fx6j-w5w5-h468",
  "modified" : "2026-07-08T17:35:00Z",
  "published" : "2026-05-19T15:49:25Z",
  "aliases" : [ "CVE-2026-45669" ],
  "summary" : "Nuxt: Reflected XSS in `navigateTo()` external redirect",
  "details" : "### Summary\n`navigateTo()` with `external: true` generates a server-side HTML redirect body containing a `<meta http-equiv=\"refresh\">` tag. The destination URL is only sanitized by replacing `\"` with `%22`, leaving `<`, `>`, `&`, and `'` unencoded. An attacker who can influence the URL passed to `navigateTo(url, { external: true })` can break out of the `content=\"…\"` attribute and inject arbitrary HTML/JavaScript that executes under the application's origin.\n\nThis is a different root cause from CVE-2024-34343 (GHSA-vf6r-87q4-2vjf), which addressed `javascript:` protocol bypass. The issue here is triggered by any valid URL containing `>`.\n\n### Impact\nApplications that pass user-controlled input to `navigateTo(url, { external: true })` — typically via a `?next=` / `?redirect=` query parameter used for post-login or \"return to\" flows — are vulnerable to reflected cross-site scripting. The injected script runs in the context of the application's origin during the server-rendered redirect response, before the meta-refresh fires.\n\n### Details\nIn `packages/nuxt/src/app/composables/router.ts`, the SSR redirect path builds an HTML response body with only `\"` percent-encoded in the destination URL:\n\n```ts\nconst encodedLoc = location.replace(/\"/g, '%22')\nnuxtApp.ssrContext!['~renderResponse'] = {\nstatus: sanitizeStatusCode(options?.redirectCode || 302, 302),\nbody: `<!DOCTYPE html><html><head><meta http-equiv=\"refresh\" content=\"0; url=${encodedLoc}\"></head></html>`,\nheaders: { location: encodeURL(location, isExternalHost) },\n}\n```\n\nThe `Location` header is normalised through `encodeURL()` (which uses the `URL` constructor and correctly percent-encodes attribute-significant characters). The HTML body uses a narrower sanitiser. That mismatch is the root cause.\n\n### Proof of concept\n\nGlobal middleware that forwards a query parameter to `navigateTo`:\n\n```ts\n// middleware/redirect.global.ts\nexport default defineNuxtRouteMiddleware((to) => {\nconst next = to.query.next as string | undefined\nif (next) {\n return navigateTo(next, { external: true })\n}\n})\n```\n\nRequest:\n\n```\nGET /?next=https://evil.example/x><img src=x onerror=alert(document.domain)>\n```\n\nResponse body:\n\n```html\n<!DOCTYPE html><html><head><meta http-equiv=\"refresh\" content=\"0; url=https://evil.example/x><img src=x onerror=alert(document.domain)>\"></head></html>\n```\n\nThe `>` after `evil.example/x` terminates the `content=\"…\"` attribute, and the `<img onerror>` tag executes JavaScript in the application's origin before any redirect\noccurs.\n\n### Patches\nFixed in `nuxt@4.4.6` and `nuxt@3.21.6` by [#35052](https://github.com/nuxt/nuxt/pull/35052). The fix percent-encodes the full set of HTML-attribute-significant characters (`&`, `\"`, `'`, `<`, `>`) before interpolating the URL into the meta-refresh body\n\n### Workarounds\nIf you can't upgrade immediately, validate user-controlled URLs before passing them to `navigateTo(url, { external: true })`. At minimum, normalise through `new URL(input).toString()` and reject inputs containing `<` or `>` (a normalised URL with these characters is malformed and safe to refuse).",
  "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:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "nuxt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.4.3"
      }, {
        "fixed" : "3.21.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.21.5"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "nuxt"
    },
    "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-fx6j-w5w5-h468"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45669"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nuxt/nuxt/pull/35052"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nuxt/nuxt"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-83" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-19T15:49:25Z",
    "nvd_published_at" : "2026-06-12T14:16:31Z"
  }
}