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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`

Moderate severity GitHub Reviewed Published Jun 2, 2026 in nuxt/nuxt • Updated Jun 16, 2026

Package

npm nuxt (npm)

Affected versions

>= 4.0.0, < 4.4.7
< 3.21.7

Patched versions

4.4.7
3.21.7

Description

Summary

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

  1. 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. 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. 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.

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 nuxt@4.4.7 and backported to nuxt@3.21.7. The three sinks
are addressed by:

Workarounds

  • For (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 }).

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.

References

@danielroe danielroe published to nuxt/nuxt Jun 2, 2026
Published to the GitHub Advisory Database Jun 16, 2026
Reviewed Jun 16, 2026
Last updated Jun 16, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction Active
Vulnerable System Impact Metrics
Confidentiality Low
Integrity Low
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity Low
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N

EPSS score

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.

URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-c9cv-mq2m-ppp3

Source code

Credits

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