GHSA-x287-wcfc-q46c - Nuxt dev server arbitrary file read through client error reports
### Summary
A client that can connect to the dev server's HMR socket can send a `nuxt:dev:client-error` event whose message ends in an absolute file path. The dev server reads that file while building the error report, and its contents are returned in the error overlay, on the dev error channel, and in the report shown in the terminal.
### Impact
This affects the development server only; production builds contain none of this code. Affected versions are `4.6.0` to `4.6.2`.
Reading the file requires TCP access to the dev server, so the default localhost bind limits this to local processes, which can usually read the same files directly. With the dev server exposed to a network (`nuxt dev --host`, `nuxt dev --tunnel`, or a proxy onto the dev port), anyone who can reach the port can read any file the dev process can read: SSH keys, `.env` files, cloud credentials and other files outside the project. The same path is refused by Vite's `server.fs` allow list over `/_nuxt/@fs/`; the client error channel bypasses that check.
No user interaction is needed and no browser is involved: a plain WebSocket client is enough, as long as it does not send `Sec-Fetch-Site: cross-site`. A web page on another origin cannot retrieve the report: the overlay and channel endpoints reject browser requests from other origins.
Nuxt 3 is not affected.
### Patches
Fixed in `@nuxt/vite-builder` 4.6.3, which `nuxt` 4.6.3 depends on. A client-reported error is no longer turned into a compile report, and report building for it no longer reads from the filesystem; file content now comes only from the dev server's module graph.
### Workarounds
Do not expose the dev server to untrusted networks: keep the default localhost bind, and avoid `nuxt dev --host`, `nuxt dev --tunnel` and proxies onto the dev port. If the dev port was reachable from an untrusted network while a vulnerable version was running, treat any file readable by the dev process on that machine as exposed, and rotate credentials
MEDIUM
Severity & confidence
Source severitymedium
Platform severitymedium
Confidencehigh
Exploitationunknown
CVSS5.9
Affected
Vendors@nuxt
Products@nuxt/vite-builder
Reporting sources (2)
GitHub Security Advisories
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-30T23:00:48
Last updated2026-11-09T09:35:06
Ingested2026-10-30T23:16:10
FreshnessNEAR-REAL-TIME
Threat typeadvisory
Recommended action
Review the advisory and upgrade affected packages to the first patched version.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: vendor ยท Original: GitHub Security Advisories