Nuxt is an open-source web development framework for Vue.js. Prior to 3.19.0 and 4.1.0, A client-side path traversal vulnerability in Nuxt's Island payload revival mechanism allowed attackers to manipulate client-side requests to different endpoints within the same application domain when specific prerendering conditions are met. The vulnerability occurs in the client-side payload revival process (revive-payload.client.ts) where Nuxt Islands are automatically fetched when encountering serialized __nuxt_island objects. During prerendering, if an API endpoint returns user-controlled data containing a crafted __nuxt_island object, he data gets serialized with devalue.stringify and stored in the prerendered page. When a client navigates to the prerendered page, devalue.parse deserializes the payload. The Island reviver attempts to fetch /__nuxt_island/${key}.json where key could contain path traversal sequences. Update to Nuxt 3.19.0+ or 4.1.0+.

Nuxt has Client-Side Path Traversal in Nuxt Island Payload Revival