CVE-2026-114133 nuxt CVE debrief

Who should care

Defenders responsible for Nuxt applications using server islands with user-controlled data passed to `useHeadSafe` should assess exposure and prioritize remediation to prevent stored cross-site scripting attacks.

Why it matters

CVE-2026-114133 allows an attacker to achieve stored cross-site scripting on the application's origin if user-controlled data is passed to `useHeadSafe` inside a server island. Defenders should prioritize verifying and remediating vulnerable Nuxt applications.

• Stored cross-site scripting on the application's origin
• Potential for attacker-controlled data to be rendered into the page
• Need for verification of Nuxt applications using server islands with user-controlled data passed to `useHeadSafe`

Technical summary

The `useHeadSafe` function in Nuxt restricts head input to an allowlist of safe tags and attributes. However, when called inside a server island, the island renderer serialises the raw input of every head entry into the island response without marking it as safe input. This allows an attacker to achieve stored cross-site scripting on the application's origin if user-controlled data is passed to `useHeadSafe` inside a server island.

Defensive priority

Defenders should prioritize verifying and remediating Nuxt applications using server islands with user-controlled data passed to `useHeadSafe`, as an attacker could achieve stored cross-site scripting on the application's origin.

Recommended defensive actions

• Verify Nuxt applications using server islands with user-controlled data passed to `useHeadSafe`
• Remediate vulnerable Nuxt applications by updating to version 4.6.2 or later
• Monitor Nuxt applications for potential stored cross-site scripting attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and source item detail a vulnerability in Nuxt's `useHeadSafe` function when used inside server islands, allowing for stored cross-site scripting. Evidence is based on official CVE Program and NIST NVD records, as well as source item and reference data from osv_dev and GitHub.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.