GHSA-c9cv-mq2m-ppp3: Nuxt: URL-handling weaknesses in `navigateTo` and `reloadNuxtApp`: SSR open redirect, client-side script execution via the `open` option, and protocol-relative bypass in `reloadNuxtApp`
SummaryThree weaknesses in Nuxt's client-navigation URL handling, all reachable
from documented public APIs (`navigateTo` and `reloadNuxtApp`):**SSR open redirect in `navigateTo` via path-normalisation bypass.**
`navigateTo` decided whether a target was external by inspecting the raw
input with `hasProtocol(..., { acceptRelative: true })`. Inputs such as
`/..//evil.com`, `/.//evil.com`, `/%2e%2e//evil.com`, or
`/app/..//evil.com` slipped past that check because they start with
`/`, but WHATWG URL parsing then normalised them to the
protocol-relative pathname `//evil.com`. The normalised value was
written to the `Location` response header and into the
`<meta http-equiv="refresh">` body of the SSR redirect page, so a
victim's browser would resolve the redirect cross-origin to the
attacker's host.**Client-side script execution via `navigateTo({ open: ... })`.** The
client-side early-open handler called `window.open(toPath, ...)` without
applying the `isScriptProtocol` check that gates the normal `navigateTo`
path. A target of `javascript:...` (or another script-capable scheme)
passed to `navigateTo(url, { open: { ... } })` therefore executed in the
application's origin instead of being rejected.**Open redirect in `reloadNuxtApp` via protocol-relative bypass.**
`reloadNuxtApp({ path })` rejects script-capable protocols by parsing
the path with `new URL(path, window.location.href)` and checking the
resolved `protocol` against `isScriptProtocol`. Protocol-relative paths
such as `//evil.com` resolve to the current page's protocol (`https:`),
which passes that check; the value is then assigned to
`window.location.href`, which the browser treats as a cross-origin
redirect. This is the same protocol-relative bypass family as (1), in
a different sink.ImpactFor (1), the practical risk is phishing or OAuth-code theft against any
Nuxt app that forwards user-controlled input (for example a `?next=`
query parameter on a login route) into `navigateTo` on the server. The
framework documents that `navigateTo` blocks external hosts unless
`external: true` is passed, so maintainers commonly rely on it as the
safe path for post-login redirects.For (2), any app that passes a user-controlled URL into
`navigateTo(url, { open: { ... } })` was vulnerable to reflected XSS in
the application's first-party origin.For (3), any app that forwards user-controlled input into
`reloadNuxtApp({ path })` could be redirected cross-origin for phishing
or OAuth-code theft, even on releases that already shipped the
`isScriptProtocol` guard added by [#35115](https://github.com/nuxt/nuxt/pull/35115).PatchesFixed in `nuxt@4.4.7` and backported to `nuxt@3.21.7`. The three sinks
are addressed by:Path-normalisation bypass in `navigateTo`:4.x: commit [`2cce6fb0`](https://github.com/nuxt/nuxt/commit/2cce6fb02e621196d56df92e05594e07469b5a6d)3.x: commit [`1f2dd5e7`](https://github.com/nuxt/nuxt/commit/1f2dd5e78c77576437138e97671965573c232835)`navigateTo({ open })` script-protocol guard:4.x: [#35206](https://github.com/nuxt/nuxt/pull/35206) (commit [`3394716d`](https://github.com/nuxt/nuxt/commit/3394716d4a913cba904b028df5338f2aead50032))3.x: commit [`62fc32ed`](https://github.com/nuxt/nuxt/commit/62fc32eddf648b00a3890141e0235d2a222b024d)Protocol-relative bypass in `reloadNuxtApp`:4.x: commit [`e447a793`](https://github.com/nuxt/nuxt/commit/e447a793c47766834f7497f8412a76cd56fd8ee1)3.x: commit [`6497d99d`](https://github.com/nuxt/nuxt/commit/6497d99dd106254abd089f6a263d7773869a343b)WorkaroundsFor (1): validate redirect targets before passing them to `navigateTo`,
for example reject any input where
`new URL(target, 'http://localhost').pathname` starts with `//`, or
only accept a known allow-list of paths.For (2): reject any user-controlled URL whose protocol is not in an
allow-list (typically just `http:` and `https:`) before passing it to
`navigateTo({ open: ... })`.For (3): same shape as (1). Reject paths starting with `//` (or where
`new URL(path, window.location.href).host !== window.location.host`)
before passing to `reloadNuxtApp({ path })`.ReferencesCWE-601: URL Redirection to Untrusted Site ('Open Redirect')CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CreditsReported by Anthropic / Claude as `ANT-2026-S08HN6DH` through Anthropic's
coordinated vulnerability disclosure programme.The `reloadNuxtApp` protocol-relative bypass (sink 3) was independently
reported by [@alcls01111](https://github.com/alcls01111) via GitHub's
coordinated disclosure flow (`GHSA-w7fp-2cfv-4837`), closed as a
duplicate of this advisory.
CVSS v4.0: 5.1