Executive Summary

CVE-2026-56317 is a cross-site scripting (XSS) vulnerability in Nuxt.js versions before 4.4.7 and 3.x versions before 3.21.7. It occurs in the globally registered <NoScript> component, which writes slot content directly to the innerHTML of the <noscript> tag without escaping it. This allows attackers to inject malicious scripts through untrusted data, such as route.query parameters, which then execute in the document context when the <noscript> tag is implicitly closed by script tags.

The vulnerability arises because the HTML parser treats the content inside the <noscript> tag in the head section in a way that any tag other than <link>, <meta>, <noframes>, or <style> implicitly closes the <noscript> tag, enabling injected scripts to run.

This issue was fixed by escaping the slot content using escapeHtml and writing it to textContent instead of innerHTML, preventing script execution.

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Impact Analysis

This vulnerability can allow attackers to execute malicious scripts in the context of your web application by injecting untrusted data into the <NoScript> component slots. Such script execution can lead to unauthorized actions, data theft, or manipulation of the web page content.

However, the severity of this vulnerability is rated low (CVSS score 2.3) due to limited exploitability and impact.

To mitigate the risk, it is recommended to update Nuxt.js to versions 4.4.7 or 3.21.7 or later, or avoid interpolating untrusted input into <NoScript> slots and sanitize any dynamic content before rendering.

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Detection Guidance

This vulnerability involves the Nuxt.js <NoScript> component writing untrusted slot content directly to innerHTML without escaping, which can lead to cross-site scripting (XSS) attacks. Detection involves checking if your Nuxt.js application is running a vulnerable version (4.0.0 to 4.4.6 or 3.21.0 to 3.21.6) and if untrusted data such as route.query parameters are interpolated into <NoScript> slots.

To detect the vulnerability on your system, you can:

• Check the Nuxt.js version used in your project by running: `npm list nuxt` or `yarn list nuxt`.
• Search your codebase for usage of the <NoScript> component with dynamic slot content, especially interpolations like `{{ route.query.* }}`.
• Inspect server-rendered HTML responses for <noscript> tags containing unescaped HTML or script tags that could indicate injection.
• Use web vulnerability scanners or browser developer tools to test if injecting script payloads into route.query parameters results in script execution within the <noscript> tag.

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Mitigation Strategies

Immediate mitigation steps for this vulnerability include:

• Upgrade Nuxt.js to version 4.4.7 or later, or 3.21.7 or later, where the vulnerability is fixed by escaping slot content and using textContent instead of innerHTML.
• Avoid interpolating untrusted input, such as route.query parameters, directly into <NoScript> slots.
• Sanitize or escape any dynamic content before rendering it inside <NoScript> components as a temporary workaround.

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Compliance Impact

The CVE-2026-56317 vulnerability is a cross-site scripting (XSS) issue in Nuxt.js that allows attackers to inject malicious scripts through untrusted data. Such vulnerabilities can potentially lead to unauthorized access or manipulation of user data.

While the provided context and resources do not explicitly mention compliance with standards like GDPR or HIPAA, XSS vulnerabilities generally pose risks to data confidentiality and integrity, which are critical aspects of these regulations.

Organizations using affected Nuxt.js versions without applying the patch or proper mitigations may face increased risk of data breaches or unauthorized data exposure, potentially impacting their compliance posture under regulations that require protection of personal or sensitive information.

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