GHSA-m3q2-p4fw-w38m
Cross-site scripting via <NoScript> slot content in Nuxt's head components
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
nuxtnpmDescription
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-escapexat the source. - If you must render dynamic noscript content, write the tag yourself via
useHead({ noscript: [{ textContent: escapedValue }] })after escapingescapedValue.
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | nuxt | ≥ 4.0.0&&< 4.4.7 | 4.4.7 |
| 📦npm | nuxt | all versions | 3.21.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nuxt. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nuxt to 4.4.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m3q2-p4fw-w38m is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-m3q2-p4fw-w38m is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-m3q2-p4fw-w38m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-m3q2-p4fw-w38m in your dependencies?
O3 detects GHSA-m3q2-p4fw-w38m across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.