Nuxt versions 4.0.0 before 4.4.7 and 3.x before 3.21.7 contain a server-side open redirect vulnerability in navigateTo that fails to properly validate path-normalized payloads like /..//evil.com and /.//evil.com. Attackers can bypass external-host checks using path-normalization techniques to redirect users to attacker-controlled sites via the Location header or meta-refresh, enabling phishing and OAuth authorization-code theft.

Affected: npm: nuxt

### Summary

Three weaknesses in Nuxt's client-navigation URL handling, all reachable from documented public APIs (`navigateTo` and `reloadNuxtApp`):

1. **(CVE-2026-56326) 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.

2. **(CVE-2026-56698) 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.

3. **(CVE-2026-56697) Open redirect in `reloadNuxtApp` via protocol-relative bypass.** `reloadNuxtApp({ path })` rejects script-capable protocols by parsing the path with `new URL(path…