--- id: CVE-2026-56317 aliases: - GHSA-m3q2-p4fw-w38m title: Cross-site scripting via

slot content in Nuxt's head components severity: low cwe: - CWE-79 vendor: nuxt product: nuxt ecosystem: npm affected: - 'nuxt >= 4.0.0, < 4.4.7' - nuxt < 3.21.7 patched: - nuxt 4.4.7 - nuxt 3.21.7 published: '2026-06-16' updated: '2026-09-09' sourceUpdated: '2026-09-09T23:51:01Z' source: GHSA sourceUrl: 'https://github.com/advisories/GHSA-m3q2-p4fw-w38m' references: - url: 'https://github.com/nuxt/nuxt/security/advisories/GHSA-m3q2-p4fw-w38m' - url: >- https://github.com/nuxt/nuxt/commit/4b054e9d95f8daf366cb144b52782047c511a66e - url: >- https://github.com/nuxt/nuxt/commit/7fea9fd687f1dacbfb63db5fae5839896b017a0e - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56317' - url: >- https://www.vulncheck.com/advisories/nuxt-cross-site-scripting-via-noscript-component-slot-content - url: 'https://github.com/advisories/GHSA-m3q2-p4fw-w38m' tags: - ghsa - npm epss: 0.00342 epssPercentile: 0.24992 ingestedAt: '2026-09-10T00:26:24.579Z' --- ## Overview ### 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 }}

``` would emit that value unescaped inside `

` 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 `nuxt@4.4.7` (commit [`4b054e9d`](https://github.com/nuxt/nuxt/commit/4b054e9d95f8daf366cb144b52782047c511a66e)) and backported to `nuxt@3.21.7` (commit [`7fea9fd6`](https://github.com/nuxt/nuxt/commit/7fea9fd687f1dacbfb63db5fae5839896b017a0e)). 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 }}

` 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](https://github.com/alcls01111) via GitHub's coordinated disclosure flow (`GHSA-8grp-wcq9-925q`), closed as a duplicate of this advisory. ## Affected packages - `nuxt >= 4.0.0, < 4.4.7` - `nuxt < 3.21.7` ## Remediation Upgrade to a patched release: - `nuxt 4.4.7` - `nuxt 3.21.7`