Vulnerability Details CVE-2026-6402
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-origin on responses.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 9.8%
CVSS Severity
CVSS v3 Score 5.3
Products affected by CVE-2026-6402
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cpe:2.3:a:webpack.js:webpack-dev-server:1.10.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.10.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.11.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.12.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.12.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.13.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.14.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.14.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.15.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.15.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.15.2
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.2
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.3
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.4
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cpe:2.3:a:webpack.js:webpack-dev-server:1.16.5
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cpe:2.3:a:webpack.js:webpack-dev-server:1.7.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.8.0
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cpe:2.3:a:webpack.js:webpack-dev-server:1.8.1
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cpe:2.3:a:webpack.js:webpack-dev-server:1.8.2
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cpe:2.3:a:webpack.js:webpack-dev-server:1.9.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.0.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.1.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.10.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.10.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.11.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.11.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.11.2
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cpe:2.3:a:webpack.js:webpack-dev-server:2.11.3
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cpe:2.3:a:webpack.js:webpack-dev-server:2.2.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.2.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.3.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.2
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.3
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.4
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cpe:2.3:a:webpack.js:webpack-dev-server:2.4.5
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cpe:2.3:a:webpack.js:webpack-dev-server:2.5.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.5.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.6.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.6.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.7.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.7.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.8.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.8.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.8.2
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.0
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.1
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.2
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.3
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.4
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.5
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.6
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cpe:2.3:a:webpack.js:webpack-dev-server:2.9.7
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cpe:2.3:a:webpack.js:webpack-dev-server:3.0.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.0.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.10
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.11
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.12
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.13
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.14
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.2
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.3
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.4
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.5
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.6
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.7
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.8
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cpe:2.3:a:webpack.js:webpack-dev-server:3.1.9
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cpe:2.3:a:webpack.js:webpack-dev-server:3.2.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.2.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.3.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.3.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.4.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.4.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.5.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.5.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.6.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.7.0
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cpe:2.3:a:webpack.js:webpack-dev-server:3.7.1
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cpe:2.3:a:webpack.js:webpack-dev-server:3.7.2