CVE-2026-71320

Nuxt is an open-source web development framework for Vue.js. From 3.4.0 until 3.21.10 and 4.5.1, an attacker can inject a template key through /__nuxt_island/ props into a dynamic component when vue.runtimeCompiler: true is enabled, causing template execution in the Nitro process. This issue is fixed in 3.21.10 and 4.5.1.

Nuxt is an open-source web development framework for Vue.js. From 3.4.0 until 3.21.10 and 4.5.1, an attacker can inject a template key through /__nuxt_island/ props into a dynamic component when vue.runtimeCompiler: true is enabled, causing template execution in the Nitro process. This issue is fixed in 3.21.10 and 4.5.1.

Impact

Nuxt server islands accept props via the /__nuxt_island/ endpoint. When vue.runtimeCompiler: true is enabled (off by default) and the application has a server island component that forwards props into Vue's dynamic component resolution (<component :is>, resolveDynamicComponent, or h()), an attacker can inject a template key into the island props to achieve server-side remote code execution in the Nitro process.

{ "as": { "template": "<attacker-controlled>" } }

Vue's runtime template compiler compiles and executes the attacker-controlled template in the server process. The same primitive also works on the client side when the runtime compiler is active there, though the server-side path is the primary concern.

Some component libraries expose a polymorphic as / asChild prop that forwards its value into <component :is>; @nuxt/ui (via reka-ui) is a widely used example. An application is affected if such a component receives the attacker-controlled value, provided vue.runtimeCompiler is also enabled. Note this does not require the island author to explicitly forward a prop: island props that the island component does not declare fall through as attributes onto its single root element (standard Vue attribute inheritance), so an island whose root is a polymorphic component receives the attacker's as value implicitly. These libraries are not themselves vulnerable; they are noted only because they commonly provide the dynamic-component sink.

Common configurations that satisfy the preconditions

The flaw is in Nuxt core. The library below is not itself vulnerable; it is noted because it commonly provides the dynamic-component sink an application might inadvertently expose.

• @nuxt/ui (via its underlying reka-ui primitives) exposes a polymorphic as / asChild prop that is forwarded into Vue's dynamic-component resolution. Installing @nuxt/ui does not by itself register any component as a server island. Exploitation requires the application to define an island component (a .server.vue file) whose rendered output puts the attacker-controlled value on such a component's as / asChild prop; with vue.runtimeCompiler: true, the attacker-controlled template is then compiled and executed. Because undeclared island props fall through as attributes to the single root, this can happen without any explicit binding: an island whose root is a reka-ui / @nuxt/ui component is enough. An example vulnerable island (the as value falls through to UButton, no explicit forwarding needed):

  <!-- components/MyWidget.server.vue -->
  <template>
    <UButton>Save</UButton>
  </template>
  

The island URL hash (/__nuxt_island/<Name>_<hash>.json) is a deterministic (unsalted) content hash, not an authentication token. It provides integrity relative to the URL but is not a security boundary: an attacker who knows the component name and desired props can compute a valid hash.

Mitigating factors

• vue.runtimeCompiler is off by default in Nuxt. The vast majority of Nuxt applications are not affected.
• Exploitation requires a second precondition: the application must have a server island component that puts an attacker-controlled value onto a dynamic-component path (<component :is>, resolveDynamicComponent, h(), or a polymorphic as / asChild prop). This can occur explicitly or via attribute fallthrough when the island's root is such a component.
• SSG / static deployments are largely unreachable via this vector (no server process to exploit).
• Island component names are constrained to the build-time component registry; an attacker cannot resolve arbitrary components.

Affected versions

Nuxt >=3.4.0 <3.21.10 and >=4.0.0 <4.5.1, and only when vue.runtimeCompiler: true and component islands are active. Earlier versions did not allow the Vue compiler to be enabled in the server bundle (the compiler dependencies have been…

Nuxt is an open-source web development framework for Vue.js. From 3.4.0 until 3.21.10 and 4.5.1, an attacker can inject a template key through /__nuxt_island/ props into a dynamic component when vue.runtimeCompiler: true is enabled, causing template execution in the Nitro process. This issue is fixed in 3.21.10 and 4.5.1.

Nuxt is an open-source web development framework for Vue.js. From 3.4.0 until 3.21.10 and 4.5.1, an attacker can inject a template key through /__nuxt_island/ props into a dynamic component when vue.runtimeCompiler: true is enabled, causing template execution in the Nitro process. This issue is fixed in 3.21.10 and 4.5.1.

Impact

Nuxt server islands accept props via the /__nuxt_island/ endpoint. When vue.runtimeCompiler: true is enabled (off by default) and the application has a server island component that forwards props into Vue's dynamic component resolution (<component :is>, resolveDynamicComponent, or h()), an attacker can inject a template key into the island props to achieve server-side remote code execution in the Nitro process.

{ "as": { "template": "<attacker-controlled>" } }

Vue's runtime template compiler compiles and executes the attacker-controlled template in the server process. The same primitive also works on the client side when the runtime compiler is active there, though the server-side path is the primary concern.

Some component libraries expose a polymorphic as / asChild prop that forwards its value into <component :is>; @nuxt/ui (via reka-ui) is a widely used example. An application is affected if such a component receives the attacker-controlled value, provided vue.runtimeCompiler is also enabled. Note this does not require the island author to explicitly forward a prop: island props that the island component does not declare fall through as attributes onto its single root element (standard Vue attribute inheritance), so an island whose root is a polymorphic component receives the attacker's as value implicitly. These libraries are not themselves vulnerable; they are noted only because they commonly provide the dynamic-component sink.

Common configurations that satisfy the preconditions

The flaw is in Nuxt core. The library below is not itself vulnerable; it is noted because it commonly provides the dynamic-component sink an application might inadvertently expose.

• @nuxt/ui (via its underlying reka-ui primitives) exposes a polymorphic as / asChild prop that is forwarded into Vue's dynamic-component resolution. Installing @nuxt/ui does not by itself register any component as a server island. Exploitation requires the application to define an island component (a .server.vue file) whose rendered output puts the attacker-controlled value on such a component's as / asChild prop; with vue.runtimeCompiler: true, the attacker-controlled template is then compiled and executed. Because undeclared island props fall through as attributes to the single root, this can happen without any explicit binding: an island whose root is a reka-ui / @nuxt/ui component is enough. An example vulnerable island (the as value falls through to UButton, no explicit forwarding needed):

  <!-- components/MyWidget.server.vue -->
  <template>
    <UButton>Save</UButton>
  </template>
  

The island URL hash (/__nuxt_island/<Name>_<hash>.json) is a deterministic (unsalted) content hash, not an authentication token. It provides integrity relative to the URL but is not a security boundary: an attacker who knows the component name and desired props can compute a valid hash.

Mitigating factors

• vue.runtimeCompiler is off by default in Nuxt. The vast majority of Nuxt applications are not affected.
• Exploitation requires a second precondition: the application must have a server island component that puts an attacker-controlled value onto a dynamic-component path (<component :is>, resolveDynamicComponent, h(), or a polymorphic as / asChild prop). This can occur explicitly or via attribute fallthrough when the island's root is such a component.
• SSG / static deployments are largely unreachable via this vector (no server process to exploit).
• Island component names are constrained to the build-time component registry; an attacker cannot resolve arbitrary components.

Affected versions

Nuxt >=3.4.0 <3.21.10 and >=4.0.0 <4.5.1, and only when vue.runtimeCompiler: true and component islands are active. Earlier versions did not allow the Vue compiler to be enabled in the server bundle (the compiler dependencies have been…