Overview
About vulnerability
Summary
Three weaknesses in Nuxt’s client-navigation URL handling, all reachable
from documented public APIs (navigateTo and reloadNuxtApp):
-
SSR open redirect in
navigateTovia path-normalisation bypass.navigateTodecided whether a target was external by inspecting the raw input withhasProtocol(..., { acceptRelative: true }). Inputs such as/..//evil.com,/.//evil.com,/%2e%2e//evil.com, or/app/..//evil.comslipped 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 theLocationresponse 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 calledwindow.open(toPath, ...)without applying theisScriptProtocolcheck that gates the normalnavigateTopath. A target ofjavascript:...(or another script-capable scheme) passed tonavigateTo(url, { open: { ... } })therefore executed in the application’s origin instead of being rejected. -
Open redirect in
reloadNuxtAppvia protocol-relative bypass.reloadNuxtApp({ path })rejects script-capable protocols by parsing the path withnew URL(path, window.location.href)and checking the resolvedprotocolagainstisScriptProtocol. Protocol-relative paths such as//evil.comresolve to the current page’s protocol (https:), which passes that check; the value is then assigned towindow.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.
Impact
For (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.
Patches
Fixed in [email protected] and backported to [email protected]. The three sinks
are addressed by:
- Path-normalisation bypass in
navigateTo: - 4.x: commit
2cce6fb0 - 3.x: commit
1f2dd5e7 navigateTo({ open })script-protocol guard:- 4.x: #35206 (commit
3394716d) - 3.x: commit
62fc32ed - Protocol-relative bypass in
reloadNuxtApp: - 4.x: commit
e447a793 - 3.x: commit
6497d99d
Workarounds
- For (1): validate redirect targets before passing them to
navigateTo, for example reject any input wherenew URL(target, 'http://localhost').pathnamestarts 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:andhttps:) before passing it tonavigateTo({ open: ... }). - For (3): same shape as (1). Reject paths starting with
//(or wherenew URL(path, window.location.href).host !== window.location.host) before passing toreloadNuxtApp({ path }).
References
- CWE-601: URL Redirection to Untrusted Site (‘Open Redirect’)
- CWE-79: Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)
Credits
Reported 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 via GitHub’s
coordinated disclosure flow (GHSA-w7fp-2cfv-4837), closed as a
duplicate of this advisory.
Details
- Affected packages:
- nuxt @ 0.10.7 (+59 more)
Summary
Three weaknesses in Nuxt’s client-navigation URL handling, all reachable
from documented public APIs (navigateTo and reloadNuxtApp):
-
SSR open redirect in
navigateTovia path-normalisation bypass.navigateTodecided whether a target was external by inspecting the raw input withhasProtocol(..., { acceptRelative: true }). Inputs such as/..//evil.com,/.//evil.com,/%2e%2e//evil.com, or/app/..//evil.comslipped 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 theLocationresponse 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 calledwindow.open(toPath, ...)without applying theisScriptProtocolcheck that gates the normalnavigateTopath. A target ofjavascript:...(or another script-capable scheme) passed tonavigateTo(url, { open: { ... } })therefore executed in the application’s origin instead of being rejected. -
Open redirect in
reloadNuxtAppvia protocol-relative bypass.reloadNuxtApp({ path })rejects script-capable protocols by parsing the path withnew URL(path, window.location.href)and checking the resolvedprotocolagainstisScriptProtocol. Protocol-relative paths such as//evil.comresolve to the current page’s protocol (https:), which passes that check; the value is then assigned towindow.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.
Impact
For (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.
Patches
Fixed in [email protected] and backported to [email protected]. The three sinks
are addressed by:
- Path-normalisation bypass in
navigateTo: - 4.x: commit
2cce6fb0 - 3.x: commit
1f2dd5e7 navigateTo({ open })script-protocol guard:- 4.x: #35206 (commit
3394716d) - 3.x: commit
62fc32ed - Protocol-relative bypass in
reloadNuxtApp: - 4.x: commit
e447a793 - 3.x: commit
6497d99d
Workarounds
- For (1): validate redirect targets before passing them to
navigateTo, for example reject any input wherenew URL(target, 'http://localhost').pathnamestarts 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:andhttps:) before passing it tonavigateTo({ open: ... }). - For (3): same shape as (1). Reject paths starting with
//(or wherenew URL(path, window.location.href).host !== window.location.host) before passing toreloadNuxtApp({ path }).
References
- CWE-601: URL Redirection to Untrusted Site (‘Open Redirect’)
- CWE-79: Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)
Credits
Reported 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 via GitHub’s
coordinated disclosure flow (GHSA-w7fp-2cfv-4837), closed as a
duplicate of this advisory.