CVE-2026-9595

A flaw was found in webpack-dev-server. When a user configures a proxy with a broad context, such as '/', and enables WebSocket ws: true forwarding, the development server's own Hot Module Replacement HMR WebSocket can be intercepted. This interception leads to the leakage of the browser's cookie...

Linux Distros Unpatched Vulnerability : CVE-2026-9595

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - Impact: When a user-configured proxy on webpack-dev-server has a broad context e.g. / and ws: true, it also intercepts the dev server's own HMR WebSocket and...

EUVD-2026-36729

webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies...

Unintended Proxy or Intermediary ('Confused Deputy')

Overview org.webjars.npm:webpack-dev-server is an Uses webpack with a development server that provides live reloading. It should be used for development only. Affected versions of this package are vulnerable to Unintended Proxy or Intermediary 'Confused Deputy' via permissive user proxy...

Unintended Proxy or Intermediary ('Confused Deputy')

Overview webpack-dev-server is an Uses webpack with a development server that provides live reloading. It should be used for development only. Affected versions of this package are vulnerable to Unintended Proxy or Intermediary 'Confused Deputy' via permissive user proxy configurations that inclu...

CVE-2026-9595

Impact: When a user-configured proxy on webpack-dev-server has a broad context e.g. / and ws: true, it also intercepts the dev server's own HMR WebSocket and forwards it to the proxy target. This leaks the browser's cookies and Origin header to the backend, bypasses the dev server's Host/Origin...