Nuxt up to 3.21.5/4.4.5 /__nuxt_island/ cross site scripting

Summaryinfo

A vulnerability classified as problematic was found in Nuxt up to 3.21.5/4.4.5. Affected by this issue is some unknown functionality of the file /__nuxt_island/. Such manipulation leads to cross site scripting. This vulnerability is referenced as CVE-2026-46342. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Nuxt up to 3.21.5/4.4.5 and classified as problematic. Affected by this issue is an unknown function of the file /__nuxt_island/. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

Nuxt is an open-source web development framework for Vue.js. In Nuxt versions 3.1.0 to before 3.21.6 and 4.0.0-alpha.1 to before 4.4.6 and @nuxt/nitro-server versions 3.20.0 to before 3.21.6 and 4.0.0-alpha.1 to before 4.4.6, the /__nuxt_island/* endpoint accepts attacker-controlled props query/body parameters and renders any island component without verifying that the URL-resident hash (_.json) was actually issued for those inputs by . The hash is computed and embedded client-side but never validated server-side, so the same path can return materially different responses depending on the query. This issue has been patched in versions 3.21.6 and 4.4.6.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-46342 since 05/13/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 3.21.6 or 4.4.6 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36418). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Nuxt

Version

• 3.21.0
• 3.21.1
• 3.21.2
• 3.21.3
• 3.21.4
• 3.21.5
• 4.4.0
• 4.4.1
• 4.4.2
• 4.4.3
• 4.4.4
• 4.4.5

Website

• Product: https://github.com/nuxt/nuxt/

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Once again VulDB remains the best source for vulnerability data.

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