# CVE-2018-14732: webpack-dev-server missing origin validation in WebSocket

Source: https://junglewise.ai/threats/cve-2018-14732-webpack-dev-server-missing-origin-validation-in-websocket  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2019-01-04. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2018-14732 · Severity: low · CVSS 3 · Published 2019-01-04

webpack-dev-server is a development server used by JavaScript developers to test and debug applications locally. The Hot Module Replacement (HMR) feature uses a WebSocket connection to enable live code updates without manual reloading. Due to missing origin validation, an attacker on the network can exploit this to steal a developer's source code by intercepting and reading messages intended only for legitimate development sessions.

Technologies: [webpack-dev-server (npm)](https://junglewise.ai/threats/technologies/webpack-dev-server). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2018-14732 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2018-14732 being exploited in the wild.

**How severe is CVE-2018-14732?** Low severity, with a CVSS score of 3, published 4 January 2019.

**Which products and versions are affected?** webpack-dev-server (npm) SEMVER:introduced=0,fixed=3.1.11.

**Is there a fix for CVE-2018-14732?** Yes. webpack-dev-server (npm): upgrade to 3.1.11 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2018-14732 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2018-14732?** Check whether you run webpack-dev-server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- webpack-dev-server (npm): upgrade to 3.1.11 or later

  ```sh
  npm install webpack-dev-server@3.1.11
  ```


## Technical details

The vulnerability is an improper input validation issue (CWE-20) in the WebSocket server used for Hot Module Replacement in webpack-dev-server versions prior to 3.1.11. The WebSocket server fails to validate the Origin header of incoming requests, allowing any remote attacker to establish a connection and receive source code being served to legitimate developers. This is a network-level attack requiring no authentication or user interaction—an attacker can simply craft a malicious web page that connects to a developer's local webpack-dev-server and extracts source code. The fix was released in version 3.1.11, which adds proper origin validation.

## Affected products

- webpack webpack-dev-server before 3.1.11

## Identifiers

- CVE-2018-14732
- GHSA-cf66-xwfp-gvc4

## Timeline

- 2018-07-24: disclosed: Vulnerability reported to webpack-dev-server project
- 2018-12-21: patched: Fixed in version 3.1.11
- 2019-01-04: advisory: GHSA-cf66-xwfp-gvc4 published

## References

- [https://github.com/webpack/webpack-dev-server/issues/1445](https://github.com/webpack/webpack-dev-server/issues/1445)

## Related threats

- [webpack webpack-dev-server Denial of Service via malformed headers](https://junglewise.ai/threats/cve-2026-14631-webpack-webpack-dev-server-denial-of-service-via-malformed)
- [webpack webpack-dev-server CSRF in developer endpoints](https://junglewise.ai/threats/cve-2026-14620-webpack-webpack-dev-server-csrf-in-developer-endpoints)
- [webpack-dev-server HMR WebSocket interception via permissive proxies](https://junglewise.ai/threats/cve-2026-9595-webpack-dev-server-hmr-websocket-interception-via-permissive)
- [webpack webpack-dev-server cross-origin source code exposure](https://junglewise.ai/threats/cve-2026-6402-webpack-webpack-dev-server-cross-origin-source-code-exposure)
- [webpack-dev-server source code disclosure via WebSocket in non-Chromium browsers](https://junglewise.ai/threats/cve-2025-30360-webpack-dev-server-source-code-disclosure-via-websocket-in-non)