{"id":"CVE-2026-6402","published":"2026-05-12T07:45:21Z","modified":"2026-05-12T13:00:06Z","title":"webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins","vendor":"webpack-dev-server","product":"webpack-dev-server","tier":"tail","description":{"text":"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.","provenance":"source","from":"CVE.org"},"cvss":{"score":5.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.00291,"percentile":0.21732,"provenance":"source"},"cwes":[{"id":"CWE-749","name":"Exposed Dangerous Method or Function"}],"references":[{"url":"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w","tags":[]},{"url":"https://cna.openjsf.org/security-advisories.html","tags":[]}],"priority":{"score":8.1,"factors":[{"name":"EPSS percentile","points":4.35},{"name":"CVSS severity","points":3.71}]},"vendorSlug":"webpack-dev-server","affectedVersions":[{"vendor":"webpack-dev-server","product":"webpack-dev-server","versions":["< 5.2.4"]}],"affected":[{"ecosystem":"npm","package":"webpack-dev-server","vulnerableRanges":["<5.2.4"],"patched":["5.2.4"],"from":["GHSA-79cf-xcqc-c78w"],"provenance":"source"}],"euvd":{"id":"EUVD-2026-29404","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-webpack-dev-server-cve-2025-30359","parents":[{"from":"CVE-2025-30359","to":"CVE-2026-6402","relation":"related","confidence":"high","kind":"lineage","evidence":[{"kind":"osv-related","provenance":"source","id":"GHSA-79cf-xcqc-c78w","via":"reference","url":"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-4v9v-hfq4-rm2v"}]},{"from":"CVE-2025-30360","to":"CVE-2026-6402","relation":"successor","confidence":"high","kind":"lineage","evidence":[{"kind":"osv-related","provenance":"source","id":"GHSA-79cf-xcqc-c78w","via":"reference","url":"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-9jgg-88mc-972h"},{"kind":"version-step","provenance":"source","package":"npm:webpack-dev-server","fromFixed":"5.2.1","toFixed":"5.2.4","daysApart":343}]}],"packageHistory":[{"cve":"CVE-2018-14732","published":"2018-09-21","fixed":"3.1.11","kev":false},{"cve":"CVE-2025-30359","published":"2025-06-03","fixed":"5.2.1","kev":false},{"cve":"CVE-2025-30360","published":"2025-06-03","fixed":"5.2.1","kev":false},{"cve":"CVE-2026-6402","published":"2026-05-12","fixed":"5.2.4","kev":false},{"cve":"CVE-2026-9595","published":"2026-06-15","fixed":"5.2.5","kev":false,"link":{"from":"CVE-2026-6402","to":"CVE-2026-9595","relation":"successor","confidence":"low","kind":"sequence","evidence":[{"kind":"version-step","provenance":"source","package":"npm:webpack-dev-server","fromFixed":"5.2.4","toFixed":"5.2.5","daysApart":34}]}},{"cve":"CVE-2026-14620","published":"2026-07-03","fixed":"5.2.6","kev":false},{"cve":"CVE-2026-14631","published":"2026-07-03","fixed":"5.2.6","kev":false}],"package":"npm:webpack-dev-server"}}