CVE-2025-30360 webpack-dev-server users' source code may be stolen when they access a malicious web site with non-Chromium based browser
Attackers can steal source code from developers using webpack-dev-server by bypassing Origin header checks via IP-based origins in non-Chromium browsers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-30360?
CVE-2025-30360 is a medium-severity vulnerability in webpack-dev-server, published on 3 Jun 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-346
Which versions are affected by CVE-2025-30360?
2 open source packages ship an affected version, including webpack-dev-server. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
webpack-dev-server npm | All versions | 5.2.1 |
webpack-dev-server npm | All versions | 5.2.1 |
Products include Webpack.js Webpack-Dev-Server.
How do I fix CVE-2025-30360?
Upgrade webpack-dev-server to 5.2.1 or later.
Is CVE-2025-30360 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-30360 exists.
Other vulnerabilities in webpack-dev-server
- CVE-2026-112085 webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades
- CVE-2018-14732 Missing Origin Validation in webpack-dev-server
- CVE-2026-114348 webpack-dev-server vulnerable to information disclosure via Host validation bypass in the open-editor endpoint
- CVE-2026-14631 webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header
- CVE-2026-9595 webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies
Sources
Also known as CLEANSTART-2026-HE65111, CLEANSTART-2026-YT66630, GHSA-9jgg-88mc-972h, MINI-cgh5-67qh-qf5r, MINI-whq3-x92q-fj72, ROOT-APP-NPM-CVE-2025-30360.