GHSA-534h-c3cw-v3h9 is a medium-severity (CVSS 5.5) Incorrect Default Permissions vulnerability in nuxt. O3 Security confirms whether GHSA-534h-c3cw-v3h9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Nuxt dev server vite-node IPC socket is world-connectable on Linux
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-534h-c3cw-v3h9.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-534h-c3cw-v3h9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 370,894 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
nuxtnpmDescription
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-<pid>-<ts>.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/<dev>/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 0600s 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 devinside 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/unixvisibility viahidepid=2mount 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | nuxt | ≥ 4.0.0&&< 4.4.7 | 4.4.7 |
| 📦npm | nuxt | ≥ 3.18.0&&< 3.21.7 | 3.21.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nuxt. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nuxt to 4.4.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-534h-c3cw-v3h9 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-534h-c3cw-v3h9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-534h-c3cw-v3h9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-534h-c3cw-v3h9 in your dependencies?
O3 detects GHSA-534h-c3cw-v3h9 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.