CVE-2026-46342: Nuxt: `__nuxt_island` endpoint does not bind responses to request props, enabling shared-cache poisoning

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-12 · updated 2026-06-17
Weakness: CWE-79

Description

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 (<Name>_<hashId>.json) was actually issued for those inputs by <NuxtIsland>. 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.

Affected products

nuxt: from 3.1.0 before 3.21.6; from 4.0.0 before 4.4.5 — fixed in 3.21.6, 4.4.5
Nuxt/Nitro-Server: from 3.20.0 before 3.21.6; from 4.2.0 before 4.4.6 — fixed in 3.21.6, 4.4.6

How to fix

Upgrade to a fixed version: nuxt 3.21.6, 4.4.5; Nuxt/Nitro-Server 3.21.6, 4.4.6. Check the vendor advisory for mitigations.

References

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