Exposed Dangerous Method or Function Affecting webpack-dev-server package, versions <5.2.4
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-WEBPACKDEVSERVER-16642067
- published12 May 2026
- disclosed12 May 2026
- creditsapphi-red
Introduced: 12 May 2026
CVE-2026-6402 (opens in a new tab)How to fix?
Upgrade webpack-dev-server to version 5.2.4 or higher.
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 Exposed Dangerous Method or Function in Server.js, when handling non-HTTPS responses. An attacker can expose source code by tricking a developer into visiting a malicious site that retrieves the code via <script> element. This is only exploitable while the development server is running over plain HTTP, by the attacker guessing the target host and port.
Note: This is a bypass of the fix for the vulnerability described in CVE-2025-30359, which blocks the cross-origin leak for trusted (HTTPS) connections only.