How severe is CVE-2026-56317?

No CVSS score has been assigned to CVE-2026-56317 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-56317?

CVE-2026-56317 affects the following packages: nuxt (npm), nuxt (npm). Ecosystems affected: npm.

How do I fix CVE-2026-56317?

Update nuxt to 4.4.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56317 is resolved across your whole dependency graph.

How do I detect CVE-2026-56317 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nuxt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-56317 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-56317 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-56317 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-56317?

CVE-2026-56317 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 26th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-56317?

CVE-2026-56317 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-56317 published, and has it been updated?

CVE-2026-56317 was published on June 20, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-56317 — nuxt

Fix: nuxt/nuxt@4b054e9

CVE-2026-56317 is a Cross-site Scripting (XSS) vulnerability in nuxt. A fix is available for nuxt — see the affected versions and patch details below.

Nuxt - Cross-Site Scripting via NoScript Component Slot Content

Also known asGHSA-m3q2-p4fw-w38m

Published

Jun 20, 2026

Updated

Oct 21, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56317.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs26th percentile — riskier than 26% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

779other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

nuxtnpm

1.5Mdownloads / week

Description

Impact

Nuxt's globally registered <NoScript> component (from @unhead/vue head components, re-exported by Nuxt) wrote its default-slot content to the innerHTML of the <noscript> head tag, bypassing the HTML escaping that {{ }} interpolation normally applies in Vue templates.

Applications that placed untrusted, attacker-controllable data inside a <NoScript> slot, for example:

<NoScript>{{ route.query.banner }}</NoScript>

would emit that value unescaped inside <noscript> in the server-rendered HTML. With scripting enabled, the HTML parser treats <noscript> content in <head> under the "in head noscript" insertion mode: any tag other than link, meta, noframes, or style implicitly closes <noscript> and is re-processed in the head. A payload such as <script>...</script> therefore escapes the element and executes in the document context.

Sibling head components (<Style>, <Title>) were not affected because they already routed slot text through the safe textContent path.

Affected versions

All currently supported versions of nuxt that ship the <NoScript> global component.

Patches

Fixed in [email protected] (commit 4b054e9d) and backported to [email protected] (commit 7fea9fd6). The fix escapes <NoScript> slot content with escapeHtml from @vue/shared and writes it to textContent rather than innerHTML. Slot content is now rendered as text; intentional markup inside <NoScript> is no longer parsed as HTML.

Workarounds

Until you can upgrade:

Do not interpolate untrusted input into <NoScript> slots. Replace <NoScript>{{ x }}</NoScript> with a static string, or sanitise / HTML-escape x at the source.
If you must render dynamic noscript content, write the tag yourself via useHead({ noscript: [{ textContent: escapedValue }] }) after escaping escapedValue.

Credit

Reported to Anthropic's coordinated vulnerability disclosure pipeline by Claude (Anthropic's AI assistant) and triaged by the Anthropic security team. Reference: ANT-2026-4NJYDFFM.

Independently reported by @alcls01111 via GitHub's coordinated disclosure flow (GHSA-8grp-wcq9-925q), closed as a duplicate of this advisory.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`nuxt`	≥ 4.0.0&&< 4.4.7	4.4.7`npm install nuxt@4.4.7`
📦npm	`nuxt`	all versions	3.21.7`npm install nuxt@3.21.7`

Affected Products

1 product · 2 configurations

Application

nuxtnuxt

≥ 4.0.0 && < 4.4.7

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nuxt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nuxt to 4.4.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56317 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Impact Nuxt's globally registered `<NoScript>` component (from `@unhead/vue` head components, re-exported by Nuxt) wrote its default-slot content to the `innerHTML` of the `<noscript>` head tag, bypassing the HTML escaping that `{{ }}` interpolation normally applies in Vue templates. Applications that placed untrusted, attacker-controllable data inside a `<NoScript>` slot, for example: ```vue <NoScript>{{ route.query.banner }}</NoScript> ``` would emit that value unescaped inside `<noscript>` in the server-rendered HTML. With scripting enabled, the HTML parser treats `<noscript>` conte

O3 Security · Impact-Aware SCA

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