GHSA-9473-5f9j-94wq: Nuxt: Server-Side Remote Code Execution via Runtime Template Injection in Nuxt Server Island Props

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 compo