GHSA-GJ2H-2FPW-FHV9

Vulnerability from github – Published: 2026-07-02 20:16 – Updated: 2026-07-02 20:16
VLAI
Summary
@nuxt/ui: UAuthForm / UForm SSR markup omits `method`, leaking credentials via GET if submitted before hydration
Details

Summary

UForm and UAuthForm render a server-side <form> element with no method and no action attribute, relying on a hydrated @submit.prevent handler to intercept submission. If a user submits the form before Vue hydration has attached the handler (autofill plus Enter on a slow network, JS bundle blocked by CSP or CDN failure, etc.), the browser performs the native default: a GET to the current URL with every named field, including <input type="password">, serialised into the query string.

Details

src/runtime/components/Form.vue (around the template's <form> element) emits:

<component
  :is="parentBus ? 'div' : 'form'"
  :id="formId"
  ref="formRef"
  :class="ui({ class: [uiProp?.base, props.class] })"
  @submit.prevent="onSubmitWrapper"
>

No method, no action. @submit.prevent is the only thing stopping native submission, and it only exists after hydration. UAuthForm composes UForm and inherits the same shape.

The SSR snapshot of UAuthForm (test/components/__snapshots__/AuthForm.spec.ts.snap) shows the rendered markup, with <input type="password" name="password"> inside a <form> that has no method.

Proof of concept

Reported by @nimonian:

  1. Create a minimal Nuxt app with a UAuthForm.
  2. Build for production and visit in a browser with network throttling at 4G or slower.
  3. Enter credentials.
  4. Submit (or let autofill + Enter fire before hydration).

The URL becomes /login?email=…&password=…. Reproducible deterministically in Playwright by triggering submit immediately on load.

Impact

Any application using UAuthForm (or UForm with credential-shaped fields) as documented. The cleartext password lands in:

  • the address bar,
  • window.history,
  • the Referer header of every same-origin subresource fetched from the resulting URL,
  • access logs of any reverse proxy, CDN, or WAF that records request URLs.

Patch

Default the rendered <form> to method="post" so the pre-hydration fallback submits as POST rather than GET. Vue's @submit.prevent still intercepts the hydrated case; the attribute only matters in the race window. Applications that explicitly want native GET submission can opt back in by passing method="get".

Credit

Reported by @nimonian. Originally filed as GHSA-92g7-2fpq-hmq8 against nuxt/nuxt; moved here because the affected code lives in @nuxt/ui.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@nuxt/ui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "4.7.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-598"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-02T20:16:12Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n`UForm` and `UAuthForm` render a server-side `\u003cform\u003e` element with no `method` and no `action` attribute, relying on a hydrated `@submit.prevent` handler to intercept submission. If a user submits the form before Vue hydration has attached the handler (autofill plus Enter on a slow network, JS bundle blocked by CSP or CDN failure, etc.), the browser performs the native default: a `GET` to the current URL with every named field, including `\u003cinput type=\"password\"\u003e`, serialised into the query string.\n\n### Details\n\n`src/runtime/components/Form.vue` (around the template\u0027s `\u003cform\u003e` element) emits:\n\n```vue\n\u003ccomponent\n  :is=\"parentBus ? \u0027div\u0027 : \u0027form\u0027\"\n  :id=\"formId\"\n  ref=\"formRef\"\n  :class=\"ui({ class: [uiProp?.base, props.class] })\"\n  @submit.prevent=\"onSubmitWrapper\"\n\u003e\n```\n\nNo `method`, no `action`. `@submit.prevent` is the only thing stopping native submission, and it only exists after hydration. `UAuthForm` composes `UForm` and inherits the same shape.\n\nThe SSR snapshot of `UAuthForm` (`test/components/__snapshots__/AuthForm.spec.ts.snap`) shows the rendered markup, with `\u003cinput type=\"password\" name=\"password\"\u003e` inside a `\u003cform\u003e` that has no `method`.\n\n### Proof of concept\n\nReported by @nimonian:\n\n1. Create a minimal Nuxt app with a `UAuthForm`.\n2. Build for production and visit in a browser with network throttling at 4G or slower.\n3. Enter credentials.\n4. Submit (or let autofill + Enter fire before hydration).\n\nThe URL becomes `/login?email=\u2026\u0026password=\u2026`. Reproducible deterministically in Playwright by triggering submit immediately on `load`.\n\n### Impact\n\nAny application using `UAuthForm` (or `UForm` with credential-shaped fields) as documented. The cleartext password lands in:\n\n- the address bar,\n- `window.history`,\n- the `Referer` header of every same-origin subresource fetched from the resulting URL,\n- access logs of any reverse proxy, CDN, or WAF that records request URLs.\n\n### Patch\n\nDefault the rendered `\u003cform\u003e` to `method=\"post\"` so the pre-hydration fallback submits as POST rather than GET. Vue\u0027s `@submit.prevent` still intercepts the hydrated case; the attribute only matters in the race window. Applications that explicitly want native GET submission can opt back in by passing `method=\"get\"`.\n\n### Credit\n\nReported by @nimonian. Originally filed as `GHSA-92g7-2fpq-hmq8` against `nuxt/nuxt`; moved here because the affected code lives in `@nuxt/ui`.",
  "id": "GHSA-gj2h-2fpw-fhv9",
  "modified": "2026-07-02T20:16:12Z",
  "published": "2026-07-02T20:16:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nuxt/ui/security/advisories/GHSA-gj2h-2fpw-fhv9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nuxt/ui"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "@nuxt/ui: UAuthForm / UForm SSR markup omits `method`, leaking credentials via GET if submitted before hydration"
}



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