cvedb.io
CVE-2026-6402
MEDIUM · CVSS 5.3
EPSS exploitation probability: 0%
Published 2026-05-12T09:16:55.640 · Last modified 2026-06-17T11:00:47.087

Summary

webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-

Affected products

webpack.js — webpack-dev-server

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.