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:
- Create a minimal Nuxt app with a
UAuthForm.
- Build for production and visit in a browser with network throttling at 4G or slower.
- Enter credentials.
- 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.
References
Summary
UFormandUAuthFormrender a server-side<form>element with nomethodand noactionattribute, relying on a hydrated@submit.preventhandler 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: aGETto 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:No
method, noaction.@submit.preventis the only thing stopping native submission, and it only exists after hydration.UAuthFormcomposesUFormand 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 nomethod.Proof of concept
Reported by @nimonian:
UAuthForm.The URL becomes
/login?email=…&password=…. Reproducible deterministically in Playwright by triggering submit immediately onload.Impact
Any application using
UAuthForm(orUFormwith credential-shaped fields) as documented. The cleartext password lands in:window.history,Refererheader of every same-origin subresource fetched from the resulting URL,Patch
Default the rendered
<form>tomethod="post"so the pre-hydration fallback submits as POST rather than GET. Vue's@submit.preventstill intercepts the hydrated case; the attribute only matters in the race window. Applications that explicitly want native GET submission can opt back in by passingmethod="get".Credit
Reported by @nimonian. Originally filed as
GHSA-92g7-2fpq-hmq8againstnuxt/nuxt; moved here because the affected code lives in@nuxt/ui.References