Threat database

A vulnerability identified as CVE-2026-112085 affects webpack-dev-server version 3.0, allowing cross-origin WebSocket access via proxied upgrades. This issue relates to improper handling of WebSocket upgrade requests that could enable unauthorized cross-origin access. No CVSS score is provided, and there is no indication of known exploits in the wild. No patch or remediation details are currently available.

webpack-dev-server allows users to use webpack with a development server that provides live reloading. Prior to version 5.2.1, webpack-dev-server users' source code may be stolen when you access a malicious web site with non-Chromium based browser. The `Origin` header is checked to prevent Cross-site WebSocket hijacking from happening, which was reported by CVE-2018-14732. But webpack-dev-server always allows IP address `Origin` headers. This allows websites that are served on IP addresses to connect WebSocket. An attacker can obtain source code via a method similar to that used to exploit CVE-2018-14732. Version 5.2.1 contains a patch for the issue.

webpack-dev-server allows users to use webpack with a development server that provides live reloading. Prior to version 5.2.1, webpack-dev-server users' source code may be stolen when they access a malicious web site. Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject a malicious script in their site and run the script. Note that the attacker has to know the port and the output entrypoint script path. Combined with prototype pollution, the attacker can get a reference to the webpack runtime variables. By using `Function::toString` against the values in `__webpack_modules__`, the attacker can get the source code. Version 5.2.1 contains a patch for the issue.