GHSA-534h-c3cw-v3h9 Nuxt dev server vite-node IPC socket is world-connectable on Linux

• npm nuxt: >= 4.0.0, < 4.4.7 → fixed in 4.4.7 • npm nuxt: >= 3.18.0, < 3.21.7 → fixed in 3.21.7

Impact When running `nuxt dev` on Linux (Node.js 20+, outside Docker / StackBlitz), Nuxt's internal vite-node IPC server binds to a Linux abstract-namespace Unix socket (`\0nuxt-vite-node--.sock`). Abstract sockets have no filesystem inode and therefore no permission bits: any local UID on the host that can read `/proc/net/unix` can enumerate the socket and connect to it. The IPC server does not perform any peer-credential or shared-secret check before dispatching requests. The `module` request type passes its `moduleId` field straight into Vite's SSR `fetchModule()`, which is not gated by Vite's HTTP-layer `server.fs.allow` deny-list. A co-resident unprivileged local user can therefore request paths like `/home//project/.env?raw` or `~/.ssh/id_rsa?raw` and read the developer's secrets through the dev server's SSR plugin pipeline. The `resolve` request type additionally enables filesystem probing. This affects developers running `nuxt dev` on shared multi-tenant Linux hosts (lab machines, shared bastions, CI runners shared between jobs without per-job container isolation). It does not affect: • Production builds (`nuxt build` / `nuxt start`). The IPC server only runs in development. • macOS or Windows developers. • Docker / StackBlitz environments, which already fall back to a filesystem socket. • Single-user laptops or per-job containerised CI. Patches Fixed in `[email protected]` (commit `1f9f4767`) and backported to `[email protected]` (commit `c293bf95`). The fix removes the abstract-namespace branch entirely. The IPC server now always binds to a filesystem Unix socket under the OS temp directory and explicitly `chmod 0600`s it after `listen()`, restricting connections to the owning UID. If the chmod fails for any reason, the server closes rather than serve requests on an unrestricted channel. Workarounds If you cannot upgrade immediately on an affected host: • Run `nuxt dev` inside a container or VM with no other tenants. Docker already triggers the filesystem-socket fallback in vulnerable versions and that fallback is unaffected. • Bind the dev process to a single-user namespace (`unshare -U`, rootless containers). • Restrict `/proc/net/unix` visibility via `hidepid=2` mount options where applicable, though this is partial mitigation only. References • Affected file: `packages/vite/src/plugins/vite-node.ts` • CWE-276: Incorrect Default Permissions Credit Reported by Anthropic / Claude as part of Anthropic's coordinated vulnerability disclosure programme, reference ANT-2026-MSNKZFAT. Thanks to the Anthropic security team for the report and the detailed reproduction. Independently reported by @alcls01111 via GitHub's coordinated disclosure flow (`GHSA-5gvc-46gq-948j`), closed as a duplicate of this advisory.